flip/flop single speed 54cm road

I PICKED THIS BIKE UP A WHILE AGO ,IT WAS A 12 SPEED ,AND HAD NO DECALS ,MY FRIEND IS A MECHANIC,WORKS AT A BIKE SHOP ,
HE SAID IT HAS A EARLY 80'S JAPNESE ROAD GEOMETRY TO IT,HE THINKS IT IS A FUJI,OR PANASONIC.,IT WAS ORIGINAL WITH A SUGINO ROAD CRANKSET,WHICH HAS BEEN REPLACED WITH A BRAND NEW PAKE SINGLE SPEED CRANKSET,NEW KMC CHAIN AND A NEW SHIMANO