Need help identifying a frame

I recently bought and built up a new old stock steel frame, and am looking to find out who built it.

The frame was bought new old stock, never built up, from Art Bikes (awesome ebay seller, based close to Bari in southern Italy). These guys normally deal in vintage, higher end stuff (think Battaglin / Colnago / Bianchi) but also some more boutique stuff too.

They have no idea what this frame could be. Although they date it to early 90s.

• Its definitely steel.
• The only marking on the frame is "52" stamped into the BB shell. This is the size, I know…
• The BB is threaded, Italian.
• The BB shell is lugged. Everything else is fillet braized.
• The dropouts look like Gipiemme, but lack the embossing.
• Internal brake cable
• External shifter cable
• No mounting points for downtube friction shifters.

Anyone out there have an idea as to who built the frame?

PS: yes, the wheels are stickered up chinacarbon… Im out here buying old frames sight unseen for 200€… you think I can afford real Mavics?