It really just depends on the prop. I've had no problems having photographs processed at Costco, nor did I have any problems with the printer at school who ran off my high quality posters.
Take the copyright off if you're going to do a poster. At worst, many places will ask you to sign a liability release stating that you're representing these items as your own work. They don't want to get sued as the printer.
I can run off a poster for you at my school (if they have their printer fixed by now), but it'll cost a little more due to shipping and overhead than you could have done locally. If you need it, drop me a PM.