Well, the 79 is a 1000 cc engine, where as the 82 is a 1100 cc engine. As far a demensions, they are the same basic block, but the gl1000 engine uses points, (unless it was converted to Dyna ignition) where as the 82 has a CDI ignition, so you will have problems with the wiring harness, which would be the biggest problem, and the gearing is different on both engines, so the gl1000 might not like the gear ratio of the 82 differental, the 82 carbs are different, but could be used on the earlier engine. It would make more sense to put the 82 engine in the earlier frame, that would be considered an upgrade, where as what you are proposing would be considered a downgrade. But it would work, if you wanted it to. Welcome to the forum!
this is an 1100 in the last months of 79 production honda used the 1100. you can believe this caused a lot of confusion when i was ordering parts especially clutch cables, and you are right it does have points,i had not considered that
Gene is spot on, whilst the engine will fit the frame, there were several other issues that make it difficult (not impossible-but difficult) and, then add in the fact the 78-9's were the poorest performers