Printing a UPS integrated label via PDF format in SB, there is a large "SAMPLE" written across the barcode - am I correct in assuming this is only because I am printing from Sandbox?

I'm surprised you got it working from Sandbox.

hmm interesting - i also found something that seemed to indicate that there was no difference between prod and sb for UPS (no test mode) so anything you do in SB is technically live as far as your UPS account is concerned