Parts for Singer IIIw155 - which "List of Parts" to use???

[LMP]

Hi all, 

I just acquired a Singer IIIw155, and went online to get the parts manual, and found two. While most of the part numbers are the same, there are many with different part numbers. I get when there is a different letter at the end, maybe for different metal compounds used, but many have very different numbers. I made a pdf of the plates side by side. I started to highlight in pink all the part numbers that are different in the two manuals, but got tired of doing so after 5 pages. But, you can get the idea.

I'm wondering if there is anything different. I tried to research if two parts (seemingly identical but with two different numbers) are inter-changeable, and apparently chatgpt thinks they are distinct parts with different functions. If you can, please see the pdf. I'd love to find out from which set of part numbers I should order and if there really is any difference. Also, I don't know what is in my existing machine, so not sure if I should worry about compatibility.  Thanks!

 

side by side of two different parts lists.pdf

[LMP]

I meant to type Singer IIIw155, not iiiw155. Thanks.

[Constabulary]

its actually 111w155 - I doubt there is a mechanical difference, maybe its a different plating on the metal parts (chrome vs nickel or vs blueing or something) either of the parts will work, I´m very sure about that.

[LMP]

3 hours ago, Constabulary said:

its actually 111w155 - I doubt there is a mechanical difference, maybe its a different plating on the metal parts (chrome vs nickel or vs blueing or something) either of the parts will work, I´m very sure about that.

ah, yes. 111. I meant to type that in my correction. Anyhow, thank you.