Walker Mower Oil Level Plug Part Number?

[consultlink]

This is the Oil Level Plug with a decal pointing to it.
This plug on both sides will not unscrew and previous mechanics have damaged them both sides. They are stuck and I can't open them without destroying them, I think. I need to order replacement parts in case I damage them further.
I cannot find a part number for this part. It is shown on the Hydrostatic Ground Drive Assemblies page and is located on the parts illustration between Parts # 10 and #11.

I want to buy two Oil Level Plugs. What part number is this?

Here's a photo of it. It has a decal next to it in Red Oil Level Plug
http://www.lawnmowerforum.com/attachment.php?attachmentid=18478&stc=1&d=1386165580

How would you handle this problem?
What phone number at Walker Mower can I phone to get a part number?

 

[mechanic mark]

Please post model, year, and all numbers you can find on mower.