To get either genuine or good quality reproduction parts, you buy them either from a mower / chainsaw shop or directly from an on line parts shop that is real, where if they sell you a dud product you can walk in & punch some one on the nose.
Lots of them around , Jacks Small engines, partsTree, e-replacement parts, Proparts direct, Messecks, K & T , Small Engine Warehouse, Small engine Suppliers, there are hundreds of them.
Amazon stores do not exist, they are just a web site & pallets at a distribution center, the prefect place to sell fake, substandard & stolen goods because you never ever know the actual identity of the actual vendor.
And in many cases the same vendor will sell the same goods at different prices using different identities.
I was at a warehouse where we did just that with our spare pallet spaces, goods arrived on a truck, orderers came in via email got picked and packed with whatever invoice we were sent .
The packers picked this up when some one was doing comparison shopping & they dispatched 6 of the same blenders to the same person but using 6 different company names on the invoices .
The blenders are a good example as they came from China in plain white boxes.
With the goods were a ream or clear plastic stickers which we ran through the colour laser printer as they were sold to brand the blenders .
And we sent out thousands of them .
If the shaft is bent the chain will run tight once every revolution so if it was a 6 tooth sprocket then the chain will go tight on every 6th drive link .
Fake Oregon chain & bars will be found on cheap imported chain saws "with Oregon chain & bar " often sold at big box stores. I doubt that a big box would risk selling fake bras & chain as a stand alone part but ebay & Amazon will .
Easy to spot because the graphics on the side of the bar are not the same as shown in the Oregon catalogue and usually the entire saw is cheaper than the list price of the bar & chain alone on Oregons web page.
I had one chain come in that had genuine branded Oregon side plates, but the cutters & drive links were fakes .
The chain had been hand made as the rivets had been spun & not riveted so some one had sat in a workshop making "genuine Oregon" chain from Oregon side plates & the rest of the bits from some one else.
The owner bought a 6 pack of these off ebay for less than I could buy the bulk chain wholesale. he brought the chains in for me to sharpen because the chainsaw shop refused to sharpen them for him . He was not happy when I did the same as the chain was wrecked despite only being used once . The cutters were so soft I would have needed to grind near 1/2 of them away to restore the proper tooth shape and the holes in all of the drive links had gone oval.
He stormed out calling me every foul name he could bring to mind at the time .
A genuine Husqvarna chain is branded as is a genuine sprocket
It will have a part number and that can be checked on their catalogue
an after market sprocket will have it's size stamped into it and a brand name if it is a better quality one along with a catalogue part number
When I see them, I check the catalogue agains the actual sprocket, if they are different it is a fake.
As Illengine mentioned the same saw can be supplied with a variety of different chains & bars so not uncommon to find a single model fitted OEM with both 3/8LP & .325 depending upon which bar it is fitted with.
Oregon have a web site where you can search you saw and find out what chains & bars it can be fitted with ,
All the other aftermarket companies will have the same catalogues although not all are on line.
Husqvarna will also have a listing but will of course only list the Husqvarna part number which you can then cross refference.
Back to your saw
Post the brand name of the parts you fitted and any numbers on them
All good bars will have a code on them that indicates what they are and what chains they can run.
Also check that the end of the bar is true to the saw
Flip the bar and see if it does the same things