[cooperino]

Originally Posted by finsruskw

Correct, it's a part number.
Only way to tell what size it is to measure from blade tip to blade tip, with them both pointing out

OR:
measure the distance between the center of the two outer pulleys.
A 42" deck will be (about) 31-1/4"

A 38" deck will be 27-7/8"

Judging from the pictures.....
Knowing this bunch....
$50

It could very well be a money pit by the time one makes it serviceable and safe with new belts, bearings, pulleys etc or whatever it might need.
But then again, you may get lucky!

Yeah... that's why I would rather trade for one in similar condition.. this way 2 people get what they need.