I can vouch that when I replaced two passenger side w123 300D doors a decade ago, a friend helped to bolt them back on. He has a good eye for alignment.
It took a few adjustments of the hinges to get good alignment.

Like other said, remove vac lines and wires from the end points of each apparatus in order to keep those lines sound and just feed through the rubber bellows.

It is a good time to inspect the metal rails of the glass for oxidation and looseness.
Swap out the rubber window 'wipers' if needed. Treat inside of door bottoms for any oxidation. Or spray with asphalt primer in order to prevent oxidation.

In my case I had to swap my regulators/motors into the donor doors and for the passenger front, replace the key tumbler with the original one so I could use original door key.

It is a two man job to reinstall and align the doors.

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1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
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1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD