Massey Harris Pony no. 812

My friend has been looking at his MH Pony, and found what he thinks is the serial number.
S/N # 12644

The operators manual says it is a Massey Harris Pony, no. 812.

15 hp, 4 cyl.

To be sure about the engine it would have been nice if somebody could tell me a little about the engine, if there were more than one type. Some says it should be a Continental N 62 engine.

What are there to look for, to be sure about the type, I think about things as exhaust on left or right side of engine, and where other things are located compared to other engines and so.

Also, how does he know what kind of distributor he has ? He says there is no plate to tell if it is a Delco or anything else.

Need to be sure before he can order any parts for it.

Thanks for all help in advance.

Bill