I got a black light the other day as a last ditch effort and it popped the sticker out like magic!  Turns out, the tractor has a swapped engine and a different deck.  It's a 917.272201 25HP v-twin 46" hydrostatic transaxle DLT lawn tractor just like the ones at the shop.  The motor was swapped for a near perfect date matched 20HP opposed twin.  Mystery solved!
As for the transaxle, I replaced the oil and it seems to work great.  It does act a little strange with bypass enabled.  It should stop any motion of the axle but it slowly reverses when full reverse and it jerks forward but only when in full forward.  I performed the purge but it didn't make much difference with the bypass issue.  Since I don't see that as a big deal (I'm not going to be running the engine in bypass for any reason I can think of), I'll not worry about it.
It looks like the electric clutch is running all the time which is a more concerning issue.  I'll have to look into that since I'm not sure about how the electric clutch engages.