In the early 850 yrs the LED didn't flash during programing so I'm unaware of any way to know if you're doing it correctly or not.

I assume then that you don't have 1 working remote?

I can't speak for people who work at other dealers but where I work, many will try to help you program a remote on an older 850 w/o charging you labor. Even a parts guy will try that to sell you the right part as it's so easy that we don't charge labor for that as it takes less than a minute. If one remote doesn't work, we'll try another if in stock. I suppose some dealer people elsewhere might not try that hard but we would. If you're close to a dealer, you could ask if they'd program that for you or if it's the wrong part, will they try another?
The only other part that could be bad is the receiver and I've maybe seen one bad receiver since 850s came out in '92.