I've had to remove springs from the B string saddle on some Schaller roller bridges for them to intonate. Seems the 5 string bridge was installed in the same location as the 4 string version. An overlooked 3/16" detail in the design. Wouldn't worry to much over it. The springs just help hold the saddle in place while changing strings. The Allen socket in the screw may not be stripped. They will stop up with crud or rust over the years. A drop of penetrating oil and some time usually loosens it up. A small pointy object to stir it up and out and there you are. Don't know the size but it's probably metric. If it is stripped and you have to remove it use needle nose pliers from the bottom if there is enough to grab. A drop of penetrating oil and some time will help there if it's necessary. The hole can be re-tapped for a commonly avaible one. If the saddles show signs of corrosion (white flaky metal) in the holes it may be time for a new bridge. The die cast aluminum is porous, swells from moisture and will really bind the small screws. I have saddles from a chrome Schaller roller soaking in a penetrating solution trying to free screws up. If the screw doesn't come out the saddle is toast unless you have a really good drill press and a carbide bit with a good machinists vice for accurate positioning and a good hold. Anymore, on anything old that passes through my hands, I disassemble the hardware and lube all the screws with a very small amount of Vaseline. Roll them between my finger and thumb. Better dust than rust.