Both Arnold and myself have a lot of experience with these kind of Basses. He has repaired and restored many of them as well as play every Bass that goes thru the shop. I have owned several Basses that were born as Blockless but were blocked when I got them. I have also played a few of them owned by other players that were still Blockless. One Bass I bought in 1975 had the raised neck block but had a block already. Some of these Basses may also have an integral Bassbar as I did shave one out of that Bass and put a Bar in it when I did the restoration on it which was one of the few I did way back when.
These Basses being at least 100 years old on average or older can sound good. Most have thin tops. Mine was a large/long 7/8ths labeled Sebastian Klotz, 1791. Was it a Klotz? I doubt it but it sounded great before I took off the top. I never played it again as it was sold just before completion to another Bassist/Repairer who was looking for a projects and he took two such Basses off my hands at that time.
My Batchelder Bass also seems to have been made Blockless as well. I mentioned the Klotz in my previous post but not the Batchelder. In either case, you can see the
Batchelder here to get an idea of what I am talking about. It has a Block and Bassbar now but due to its type of Back Construction (half mortise) it is not fully lined. This is a job Arnold may do if his bench clears up and it doesn't get sold in the mean time. It is 100% healthy at the moment but tightening up the insides (which seem to have been repaired by many people), will most likely improve the already good tone it has.