Looks like there are pins on the footers where the bottom blocks are set and the upper blocks index on the pickup points of the lower blocks. No need to weld. Nothing is going to be picking them up. May be some through bolting locations along headers between modules like bolting together a wooden modular home. The characters on the front of the first building are Chinese with the number 43. Either way, it is going to be a cold building like a full masonry block one.