Well, acoording to the other thread, it has Campagnolo hubs, so it's almost certainly a freewheel and does appear to be one.

The rear derailleur is a RD-7402, which means it's 7/8 speed compatible. Spec capacity and max. cog size are both 26T. The levers are SIS, but I can't tell if they are the 7 speed, SL-7401 or the 8 speed, SL-7402. As OFG states, they are not 6 speed.