How would you even get those hex bolts inside the print ?
laying the model down while printing you could pause at height and add the bolts (and would probably stick through the build plate ?)
printing upright would cause the print head to bump into the hex heads if you add them during the print.
if you print the right speed and temp, you might get away with bridging the gap without support, but might impact layer adhesion and the strength of the part.
I sometimes print a filler block that I can put inside a gap for another object, pause at height and put the block in (with tape on the top,
because it is a loose block and has some screw holes, I can take it out without much problem, just don't make the block too tight fit
