408 windage tray

so after i read this question im curious...i just recently bought a built 318..i know nothing about. I'm taking it apart and its like a treasure chest. haha. but when i took the 4 cap bolts that the windage tray bolts to. there were two thick washers under them (maybe 5/8" total). Is this normal? i didnt even think to look to see if the crank was a stock one. could i possibly have a stroker? how can i tell?