Yeah, they may have weight values to determine build chance, similar to how the fleet beacon abilities can.
I think they only have negative ones based on these numbers, so for some types one or two capital ships are not favoured, and the remaining have the same value.
TBH I would expect every capital ship to be built on average 1 or two times in each game if every capital ship had random chances (of course reaching this tendency after several games), but for the low numbers it was not like that. In many games there were none, remaining games only one, and 1-2 games when 2 or 3. Highest numbers had strange rows as well.
The Vasari Rebel Aggressive one had this:
in consecutive 11 games how many Skirantras were built by the 9 AI's: 0,1,0,3,0,0,0,1,1,1,0
Radiance by fortifier AR: 0,2,0,1,1,1,0,0,1,1,1
Rapture by Economist AR: 0,1,2,1,0,0,1,1,1,1,0
Sova by researcher TL: 1,0,0,2,1,0,3,1,0,0,1
Marza by economist TL: 0,1,0,0,1,0,1,2,3,1,0
These are not really the 1212121212 sequence I would expect if all ships had equal initial chances. 1 player has 16,7% chance to get any capital ship, leading to 222111 in a (perfect) game, so if we think along this line of thoughts each capital ship should have a 11222121211212 line, and the lack of 2's in the lines above is more than suspicious to me, and the presence of several high numbers in the rows below as well.
There were other strange things, look:
Fortifier TL Kol 2,1,2,3,1,2,4,2,3,1,0
Economist TL Corsev 4,4,6,0,2,2,0,0,1,2,3
Economist VR Antorak 3,3,2,2,2,2,2,5,0,0,2
Fortifier VR Vulkoras 1,1,2,0,4,1,4,2,1,2,2
Aggressive AR Rapture 2,2,3,1,3,1,3,2,3,2,2
Fortifier AR Halcyon 2,1,4,4,0,1,2,2,3,3,5
Such a wide variety of numbers, not even near the 12121212 line someone would expect.