WorM and piston

[Nacho-RT74]

I found a NOS worn and piston assemby to the steering box... On my 1974 Mopar parts catalog appears it should be PN 3643170. I don't remember the PN of the one I found but last three digits are 855 or 255. The two first are 29. My questions are:

It could be a superseded number ( 3643170 ) from the other one ?
Worn and piston assemblies are the same to all years, all cars ?

two first digits (29 ) say me that they are 68/69 year.

Don't look at lighningtjar website... the 3643170 doesn't appear on the records

[Brock Samson]

 Dammit Natch, It's "Worm" kan't you sphell?!   

[Nacho-RT74]

ooops, sorry. hehehehe... I won't say is a typo mistake, even I could because both letters are side by side on keyboard

[Nacho-RT74]

[Nacho-RT74]

Ok I found this info ( attachment )

why different numbers on 70, 71 and 74 ( my catalog says PN psoted on first reply )... some reason ? I know box it could be different, but interior parts ?

The one I found is the same posted on attachment to 71... it could be used on 74 ? it could be just a supersedes PN ?