Original jack and crank ID? Part numbers, stampings, etc?

[Brad54]

So from what I'm seeing, it looks like the bottle jacks for our trucks fit a lot of other applications as well, because I see that same style frequently.

I'm sure there are slight differences though.

What's a sure-fire way to identify these jacks?

Also, what's the best way to identify the cranks? Part number? Length measurements?

I just found what looks like an original jack and crank at the local pawn shop... but the last time I found what I though was an original crank, it turned out to be a good bit longer than a known original I compared it to.

-Brad