Bolt on hub cap on the front designates it as a 2 ton or greater. 1.5 ton only have screwed on CI hub cap. Ton ratings are sort of vague, not very useful. 2 tons came with 5/10 lug bolts which you have. That front axle allows you to replace spindles and disc brake hubs out with later(90’s) P-30 and P3500HD spindles and hubs with the same bolt pattern wheels if you wish.

Ed

'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.