someotherguy
Truly Awesome
Without an actual lookup via Compnine etc. a simple VIN decode reveals:2GCGK39N3K1245200
1st digit 2 made in Canada
2nd-3rd digits GC Chevrolet Truck division
4th digit G is the GVWR, range of 8,001-9,000 lb
5th digit K is 4WD
6th digit 3 is series, 1 ton
7th digit 9 is extended cab
8th digit N is 7.4 engine
9th digit is an internal check digit
10th digit K is 1989 year model
11th digit 1 is Oshawa Ontario plant
12th-17th actual serial #
Duallies are typically 4th digit H for 9,001-10,000 lb GVWR. With that I am 99% sure your truck is a conversion from a SRW 3500. I have records of several old parts trucks of mine that were 3500 SRW and also 2500's with 4th digit G, and duallies with 4th digit H.
Arrowcraft is a company that offered kits with spacers, wheels, etc. ...they used to offer them for GMT400's complete with the fenders. Could be one of those kits, or could be just spacers and someone sourced an OEM dually bed.
Richard