Got it running and drove it around the yard. It is an interesting machine. Pulled the deck. one spindle had the blade hit something and buggared up the plastic pulleys and froze bearings and broken gilmer belt. Middle spindle has growling bearings. Both belt idlers have shot bearings. Guy wants it fixed $$$.
It has the Bio mulching deck.
Don't know what they were worth new in the USA but they were $ 8,000 down here more with a Kawasaki engine.
The discounted ones sold for $ 5,000, just a touch more expensive than the tractor style which were $ 4,000 to $ 5,000 for a 42" deck.
Once you get used to the rear ( tiller style ) steering you will love it .
The shear pins in the blades should be zinc like the old B & S flywheel keys
New blades should ship in a box with 2 pair of pins
Very common to find some dip sheet fitted an allen bolt in place of the pins and the results of that is what you have just found .
If it is likely going to be a long term customer then slip the central cover off & lube the cables .
I know they look funny but they work really really well & as every fastener is either a no tool Dutz or the same metric size, easy to work on particularly if fitted with the Kohler or Kawakasi engines .
The ones fitted with B & S engines of course require another 7 tools .
This was one of the mowers that took 2 days to remove a rear wheel and another full day to purge the tranny.
I had to resort to putting my sump pump on the overflow reseviour to suck the air out .