A photo would help a lot. I am assuming this is a square taper five arm crank.

As long as the chainrings are bolted and not rivited to the crank arms, a five arm chainring should be easy to swap out.
https://www.sheldonbrown.com/cribsheet-bcd.html

Decades ago before chainrings started to include ramps and pins and such shifting aids, shifting was not quite as smooth. Thus you probably would end up with shifting that is less smooth, but that should not be a big deal.

In some rare cases, you might have to add a spacer washer under a chainring, but the best way to find out if you need one is to try the combination you want and see how it works. When needed it is likely if you mix 10 speed rings on an 8 or 9 speed chain. A thinner 10 speed ring can upset the spacing and require a spacer.

In the attached photo I put a generic (no name) 74mm BCD five arm 24 tooth inner chainring and a Stronglight 135mm BCD five arm 46 tooth outer chainring on my Campy crank with the stock Campy 42 tooth ring in the middle.

Eggman84 talked about a pin, you can see a small hole in the big ring in the six o'clock position, that is a small threaded hole so that I can use this chainring on any type of crank with the right bolt spacing.