@ wolfhardt: I'm glad you saved the bike; sorry about the Campagnolo parts.
The 52-49 chainring combination (or at least the three teeth difference) was pretty common in the old days. They provide a half step between the ratios of the rear cogs.

Regarding the decals: you might try to contact Wim van der Kaaij, the man who probably built the frame. Although he has retired earlier this year, his new address and phone number are in the header of his website. He may still have a set available.