as i won't have the frame for probably a month, measuring the shell width will have to wait for now. aside from the pics, this is the seller write-up..

Vintage frame set for sport bikes, light and well manufactured (we don't know the frame builder)
YEAR OF PRODUCTION
From the 40s / 50s
SPECS
Size center to center: 55 cm (seat tube),
57 cm (top tube) 13 cm (head tube)

Headset: 1"

Bottom bracket shell thread: ITALIAN
Rear dropouts spacing: 115 mm
Seatpost diameter: 26,8 mm
Weight: 2930 grams (frame, fork, headset)
Made of: steel tubes