The bike appears to be a 1985 PH 501, whic is 501 + Peugeot fork. Carbolite is proprietary to Peugeot, so the fork ishown appears to be OEM.
http://cyclespeugeot.com/PDFs/1985pdf.pdf
While, the OP's bike is one model below the PGN 10, the frame tubing is the same, and should ride great. I love my 1985, shown below.