PS--do M38 Husky actions have the thumb slot for using stripper clips?
They do, but I think you're missing something. The M38 Husqvarna IS a Mauser. It's just a small ring Mauser. Husqvarna simply refers to the location it was made in.
They do have the thumb slot; the small ring mauser action (the 93 Spanish, 94 Swedish, 96 Swedish, 38 Swedish, and probably another couple that I missed) differs from the large ring mauser action (98 German and most other Mauser actions) in the following ways:
1. As you mentioned, the large ring actions have a 3rd rear lug as a safety feature. Small ring Mausers such as the Swedish ones do not have this 3rd lug.
2. As you also mentioned, the bolt shroud was made to better handle escaping gas in the event of a pierced primer.
3. The large ring actions are a cock-on-opening design, while the small rings are cock-on-closing. Cock-on-opening is generally accepted to be the better design.
4. The large ring action is stronger. It can handle pressures much higher than the small ring action. The small ring actions could never safely handle .30-06 class cartridges whilst the large ring actions can do this without any problems.