Vahe
You may be correct. The planes sold to LOT in Poland, which shifted between the Wermacht and the Red Army are confused. If you can sort this out, we will be in your debt. However, claiming that Lockheed skipped a couple of serial numbers is too imaginitive for most of us because it has no precedent, and even in the 1930s, there were some rules about what US airplane mfgrs were required to do.
Perhaps you may have good Russian language skills, which might be a valuable search tool, since there are vague connections between these two aircraft and Russia. Take a couple of months and see what you can dig out for us. We'll assist wherever we can. On the other hand, the likelihood of finding a survivor anywhere east of Danzig looks to me like .01 or less.
BTW, do you have Romanian? My attempts in that direction all seem to produce vague tales of all airports and their contents being destroyed in the period from 1939-1945. Having had first-hand contact with the Nazis, I'd not be surprised.
Appreciate your concern and efforts.