The PP4 probably represents manufuacturer-fortnight-year. If so, the frame was manufacturred during weeks 31-32 of 1994. That would be August 1994 and late enough in the year to be the start of production of the 1995 models. It takes a lot longer to build a frame than assemble the components onto the frame, so manufacturers typically stockpile frames before building them up. Then there is the time involved in trans-oceanic shipping, customs clearance, warehousing and ditributing to the LBS. The first of new models are ususally in the LBS by early December, to take advantage of the lucrative Christmas season, so when you back things off from there, most manufacturers start building the new models around September and sometimes earlier.