So you're tellin' me. Now listen to me. LOL that's just a little joke from my part time job anywho
So as long as I don't have a computer system with a robot taking the money in a western its ok to use whatever?
LOL, I don't care if you listen to me or the others or not. You're not my kid.

And no one has all the answers anyway. (Don't let that one get out, though!)
But no, that's not what I mean, at all. And, remember, my remarks are based solely on this thread and the little I can guess from it about your WIP.
I mean that you need to consider WHY you want to use that specific item -- a cash drawer that comes out automatically -- in your WIP.
It seems that what you want to use is a real cash register, which didn't exist when you've said your WIP is set. Therefore, my question is why MUST you use an automatic drawer of any kind? Why is this important to the STORY?
If that's the ONLY way a plot point will work, then you have to ask yourself if that plot point is important enough to warrant the jumping through hoops you'll need to to do in order to make that plot point plausible to your readers/viewers. If it IS, then you have to build the plausibility. If it ISN'T, or if it is but the work you'll have to go through to build said plausibility isn't worth it, then maybe you need to consider something else, another option, that will give you the ultimate same effect.
I also brought up two very distinctly different "Westerns" as examples. "Wild, Wild West" was clearly more of a fantastical than realistic setting, ergo, if YOUR WIP is set similarly, you could do an automatic cash drawer more easily. But you'd still have to have built your entire world that way, if you will.
However, if you're striving for authenticity, more like "Lonesome Dove" (arguments for historical accuracy notwithstanding, it's FAR more realistic than WWW was), then you would have to build a plausible and believable reason for this automatic cash drawer existing.
Any contraption can be built. If you're in the time of locomotives, which you are, anything that a train does you could have someone recreate differently -- smaller, larger, to do different things, etc. And so forth for anything that existed at the time.
But this does NOT mean that "anything goes". That's up to how realistic your entire work is, not just this one plot point. If you're writing as realistically as possible, then you either need to build the plausibility or you need to alter something, possibly many things, to get the effect you're going for.