A bit confused on the subject of sleeving?

Proper sleeving has no welding involved in it. Monks patent No. 1222 of 1881 makes mention of soldering, brazing, or shrinking the tubes in place. The most commonly used is simple low temperature solder.

Welding would be a bit intense for typical gun barrel steel, and downright scary on damascus.

The guns that have been for sale on Kirk's website in the past always noted "sleeved" if that was the case. "Buyer beware" shouldn't be morphing into "gunsmith beware for buyer", unless you pay the gunsmith for that service.

If Kirk did indeed do the sleeving, safety isn't an issue.
Best,
Ted