I think it's a good idea. I did it to my '78 and love it. The sight glass may not 100% agree with the dip stick but I find it close enough for my purposes. It's good enough to tell me with just a glance if the oil is getting low and needs some added.
Any '81 and newer cover will swap right on. I found the newer cover gave a bit more clearance for my aftermarket head pipes too. That "bump" on the bottom is beveled .....