Are you talking door shell or body shell as far as filling it with 68 guts?

If you mean the body, I know it's minor but the dash area around the steering column will certainly be different because of the redesigned 69 column with the key. Shouldn't be a tough one to change/correct that issue though.

Interesting question about the doors though. Are you thinking maybe if you strip all the weatherstrip channel and all that off the body, maybe you can put 69 stuff on the 68?

I am looking at some decent 69 chevelle doors,  and using them on my 68 Beaumont.  So my thinking is, can't I just install the vent window ass. Into the 69 door shell,  and the guides and such,  I realize there will be a few holes to pinch, like the one for the vent window . To bolt in. 

Just wondered if anyone has done this.. Before I pursue it any further..

goodmark lists different part numbers for each year. 

The doorskin panel for 1968/69 Chevelle hardtops/convertibles, either a full or partial, will interchange, and here's the other applications used:

4/20/00 update:  the 1969 doorskin panel will fit 1968 hardtops with minor mods (I am sure that the doorskin panel will fit 1968-72 El Caminos, but modifications are needed for