drive tire sidewall has little dry cracking run or not

Picked up set of 5 tires 2 tread bad wanted the rims 2 decent tread 12/32 and one new recap. All on spoke hub rims. One of the decent tread has some dry cracking around tire about a inch from from rim little bit all the way around looks like not wide cracks don't seem deep. holds air 90psi last nite same this morning, would you run them or not there on a log truck 38k rears 80% on hwy driving . Maybe I should put the new cap on with the decent tire 11/32 was hoping to run them for awhile then get new caps on the 4 extra rims and change out the axle with new. The other side of axle has about 12/32 also. Only paid 140 for all 5 with rims guy retired and they were extra's he had. Opinions ???

 

I was just going to run them for a month or two then I have enough extra rims for a spare and 4 to have a new set of caps put on them so I can just swap out one axle worth of tires when ever I want I figured the 140 was worth it for the one new cap. If I can use up these decent tires a bit would be a bonus. I'll mount that one on outside so I can watch it.

 

It was capped in 04 the numbers don't make sense thou on dot numbers it reads dot 4d 3t 3e3 477 I highly doubt thats a 77 sidewall. It's a firestone de 663

 

I could run the new cap but then i would have a new one with 3 used really shouldn't from what I've read. ?

 

Can I get away with that dry cracking tire for awhile ?? Try it and carry a spare ? If I get a month out of it or two I'd be happy I'd have the new tires by then on rims waiting. I plan to change them out I hope when I do other side of axle brakes,drum,ect.