It's far too long ago for clear recollection but from what I can remember, mine went in fairly easily. In those days the "chrome" plastic trim went onto the screen, then the complete arrangement fitted into the body. Some things I can recall;
1. The manual says to use butyl rubber strips, which I assume are similar to those used on modern double glazed window panels in the UK. At the time I couldn't get this material so my screen went into both the trim & body using mastic. (the same mastic I'd been given by the windscreen supplier when I replaced the bonded screen on the Marcos I had around the same time)
2. After dry assembly to cut the new trim and make sure it would fit, everything went in at the same day. Screen stuck into trim, trim corners and the whole assembly into the body. As I mentioned before, the rear screen certainly took me two days worth of sore fingers and swearing but the front screen was much easier.
The only way I can see it taking 2 days is if it takes a day to clean the aperture and you bond the trim to the screen first and let it all set overnight before fitting to the car.
I must admit I'd be surprised if windscreen fitters do that. I've had a couple of bonded screens replaced and they seem to do the whole thing in a couple of hours, screen out/clean/new screen & final trim, all done very quickly by my standards.
Brian