I could probably talk way too much about this, so I will try to keep it fairly simple and short, at least for now.
DLX is the only brand out of BBS that uses the I to IV (1 to 4) which is the number in the stack, I (1) being the top and steepest with IV (4) being at the bottom and most mellow of the four. Very rarely some of those boards have been used for other brands, I guess around the time of pandemic issues and flat out crazy times, but none before or after that to my knowledge - someone else on here said they had a couple, as well as some DLX boards not having the I to IV and were slightly different shapes / sizes to the normal boards too, as per one I had.
All BBS presses do four boards at a time, so although no other companies boards normally show the number system, half a dozen boards from the same brand with the same shape, dimensions, graphic can be significantly different in concave and feel or could also be almost exactly the same, but you don't know where they were in stacks, could all be tops, could be bottoms, could be mixed, etc.
The other thing I have noticed is not all the presses are made equally either, with some I would say being much more mellow than others, as from time to time I get the same size board that is significantly flatter all round than any others with the usual molds, both DLX and other companies, but it is more noticeable on DLX boards as per one I got recently with I on it but it was more mellow even than all the other IV boards I had presently. I put this down to the fact that some of the bigger boards need way more mellow presses than the smaller boards, eg you couldn't have a 10" board coming out of the same press as an 8" board otherwise the bigger board would be so steep in the sides or the smaller board would be completely flat for the same amount of concave. In this way, some of the very mellow boards might have been pressed on the "big board" molds. Then there are different lengths, so different presses are needed for those, eg 14" wb boards are not done on the same presses as the 15"+ wheelbases - four fingers of flat vs no fingers of flat, if that makes sense.
Of the different brands under BBS, some are more known for consistently steeper concave (FA / Hockey or Baker B2 boards) and some for consistenly mellow concave (Baker mellow OG) so it also makes sense that there would be certain molds for specific brands or groups of brands too, but not necessarily dedicated molds just for one company.
I would think that the majority of brands under BBS use the general pool of molds, determined by size of board and wheelbase, so as said there would still be some differences in concave and angle of kicks coming out at the same time, for the same boards.
This is why some manufacturers like Dwindle have gone specifically for the single press method to ensure every single board is exactly the same, every single time, as there were ongoing issues where some people were not happy with such a significant difference in what was supposed to be two identical boards.
Edit:
* Feel free to correct me if I got any of that wrong - it is all just info I have picked up over the years, both from my own experiences and from others.