welder/welding machine question

TT5.9mag said
Doesn’t look like the older 185s have the direct option to plug in a spool gun. That’s not to say you can’t make it work.

https://www.millerwelds.com/files/owners-manuals/O1313P_MIL.pdf

This one does.... I don't know what you're considering "older". There is definitely a plug there for one and I remember there being a sticker over it bragging about the fact that it's there when I bought it brand new from what is now air has.