Yes there are several differences. The earlier coupes have the steel MLG bolted on to the front of the spar and the later aluminum ones are bolted on the back. This complicates spar replacement of the earlier models because the spars are different.
The steel trailing link is longer to make up for the difference of attachment point and come up with the same wheelbase distances. The travel is longer which I think gives a better hydraulic cushioning on landing. It might even have better cross wind landing qualities. ( speculation ) The steel spacer will work in raising the tail if inserted together with the donuts. This is much easier to do with the early gear as it does not have the "*%&$" clip ring that needs to be inserted while compressing the stack with a hydraulic press. With the steel spacer inserted, the tail will rise. However, by inserting one extra donut in the stack, ( as explained in the 337 procedure I used... I hope it is the one uploaded in the files here), the additional spacer is now also compressible adding to the spring action of the rubber donuts. Rubber donuts are cheaper than the steel spacer as well as lighter. Everybody probably has an old donut somwhere from the last change, A lightly used one may work just great for a small increase in tail height. As for using an extra donut with the aluminum MLG, I don't see why it would not work also. A spacer is a spacer.. and it makes more sense to increase the spring factor of the donut stack with an extra rubber spacer than a steel one. Both will stiffen the stack but the steel one will also reduce the travel. Alan Fairclough N87333 N94694
