I was looking online at a few of those SECs, but there were two things that I thought might be problematic:
1) SECs were not coupes designed based on a convertible (as I understand the SLC is an elongated SL that was designed after the SL... So I assume the fundamentals of the structure were designed for a convertible... unlike the SEC) !!!! EDIT !!!! - I just read that the SLC and SL were designed simultaneously, but the SL production started first. So this statement of mine appears to be false. (end edit)
2) The SEC never seemed to have a third seat belt option in the back. I'm sure I could customize the SEC back seat to put something in the middle, but with that console, it's just like the newer convertibles with that middle bolster for the two side seats. The SLC seems to have more of the old bench-seat that I require.
So here are the older pictures that I've had for a while now. The current owners purchased the car from Stephen Register in Atlanta in 1986, not too long after another one of Stephen Register's 450slc 5.0 convertibles were featured in the September 1985 Car Collector magazine article on the c107. Interestingly that September 1985 article predicted that the 107026 would be a collectible car. I guess based on current prices, it still has a ways to go before being really called collectible.
The top does need work, as you can see. Of course I'm going to try to spruce it up before I get it ripped off the car to have the custom top made.
I will miss the idea of driving with the hard top. I think it will take me a good long time before I sell the 1973, a better looking car in my opinion... but "function first".
The seller said the car came with a smaller sportier steering wheel, but he had Stephen Register swap it out for him. So maybe I'll now be seeking an AMG-style steering wheel (to match the Recaro's and basketweaves).