The canister and its lid look correct. It appears to be the same as the original AC canister on my 1949 Super, which takes a P-127 canister. (I've owned the car since 1978.) There should be a conical spring inside the cap to hold down the filter.
The Baldwin Filter P26, available from Bob's Automobilia, fits. I found that the cross-referenced filter from NAPA (I believe it to be a Wix filter) ended up being too tall, either because of shaft clearances or something else. Years ago, Fram had the correct filter, which could have been sourced from someone other than Wix.
I am puzzled, though, with your measurements. The Baldwin P26 appears to roughly measure: 4-3/16" diameter, 4-5/16" length, 1/2" shaft.