Anyone here experienced with blowers?

[markinnaples]

I'm looking at buying a 355 with a supercharger from a guy who built it for his '32 coupe but had some damage from hurricane Irma and needs the money. The block is Summit blower-prepped with all new forged internals with a GMC 6-71 blower. He said that the blower needs new seals and that the rotors need to be reversed. The engine comes with everything except carbs, distributor, intake gasket, lower blower crank pulley and belt.
Does that sound reasonable? I'm not familiar with the reversing the rotors so that's totally new to me, but just curious if anyone has had any experience in this world as it's all new to me, thanks.