I purchased a K38 today. It is a FWD Auto Co. Eagle Division Appleton, Wisconsin dated 10-19-43. The old tires are Firestone 4.00 - 18 inch and have the original valve stems. Serial number A 36. I will post pictures soon.The rims are in good conditon as well. I will need new tires and tubes.
I began sanding and found yellow numbers under what I believe is Air Force Blue. It appears the trailer had all of the olive drab sanded off at some point and was primed in red with blue paint. I did find OD under the data plate. The data plate serial number A - 36 was stenciled on the lower rear panel as well as 43 - L 3388 on the top rear panel. Not sure what 43 - L means?
The inside is clean and like new silver paint and appears to be original. The lower storage box has a little surface rust. Should the safety chain have a hook. It is attached to a ring that appears to be original?
The tires were 4.00 Firestone with original tubes and valve stems. There was a strip of rubber or a liner between the rim and tube. The strip is about 3 inches wide.
I bought my tires from Coker, but, Universal sells them for a little less with less shipping costs. I had an original tire (4.00x18) on mine and Coker makes the same tread pattern, very nice tire. Coker tire # 71350 400-18 Motorcycle Diamond Tread. Bought the tubes from them as well, Coker #86275.
Looking forward to the photos of your trailer.
Dan Schultz Retired USA SFC GPW 14944 DOD 4-10-42 M38 MC70324 DOD 6/52 M38A1 MD20035 DOD 9/52 M100 1/4 ton trailer 01177482 DOD 8/51 K-38 Lineman Trailer Apr 1943