chevyb - A little research through some various parts books and sources shows the GM# 2251489 was used in a variety of US and Canadian GMC and Chevrolet "Big Bolts".
I found it listed as fitting a 1958-59 GMC P350 (Heavy Duty 16,000 lb Forward Control Cargo Van Chassis), 1956-57 US Chevrolet Trucks Series 7-8-9-10 (all 2-1/2 ton trucks with Eaton front axles) as well as Canadian Chevy/GMC Series 1700-9700 and Series 1900-9900-W1900-W9900 (all 2-1/2 ton trucks) in just the few ready reference resources I have.
All the GM Parts books indicate its an Eaton# 32427 King Pin set, which also cross references to a TRW K439 replacement set. A TRW K439 reference seems to indicate they also fit "GMC: 1950-54; D450-37, D470-37, DW450-37, F450-37, F470-30, S450-30, HC520-600-650, HCR520-600-620-650, HCS520, HF450-520, HFR520", but I'm unable to confirm that with my resources. Perhaps someone with more GMC Parts Books can add to this info?
The only other item to note is it appears your set is missing 2 of the required 4 locking pins/nuts. This kit requires 2 locking pins for each king pin per my resource info.
Definitely some hard to find parts and hope they can find a new Stovebolt home. Best of luck sir!
