i need help with the year and model

We just got this jeep in the shop, it has a hydraulic dump bed on it. I was wondering if anyone can help me on the year of it. It runs good, you can barely even hear it running. It was two pumps on it, one for the plow and one for the dump bed.

I found this on About.com ATVS/OFFROADING if it helps


1956 START END UNITS
CJ-3B 57348 22953 34371 11418
" ST. CH. 57448 11668 11717 49
" Fire Eng 57048-01 10008 10018 11
475 4WD PU 55248 10923 11532 609
" " STK 55348 10027 10059 33
" " CAB 55148 10559 10931 372
" " C/WS 55548 10008 10613 606
" " FFC 55448 10001 10002 2
" " AMB 55048-03 10095 10104 10
" " CPC 55048-06 10012 10073 62
6-226 4WD PU 55268 22169 33446 11277
" " STK 55368 10692 11260 568
" " CAB 55168 11392 14458 3066
" " C/WS 55568 10051 10065 15
" " ST CH 55668 10002 10002 1
" " Fire Eng 55068-05 10002 -- 0
" " AMB 55068-03 10012 10040 29
CJ-5 57548 27007 45922 18915
" ST CH 57648 10011 10022 12
" C/WS 56548 10001 10006 6
" Fire Eng 57048-02 10002 10007 6
CJ-6 57748 10001 12224 2224
" ST CH 57848 10001 10002 2

It must be like a 58 then... the first series of numbers are just saying its a pickup then the last is the year as long as its between the start and end right?

We got the bed working today on it just have to replace some hydraulic lines and it should work out pretty good. I was looking through some pics on the internet and haven't saw any with a hydraulic dump bed, i'm not sure if it was added on later or came that way.

thanks for the help
matt