Brass Tacks, Some info for you - part of OSHA/ANSI/SAE design stnadards for the manufactuerer to help the end-user to be safer -a DOG is design to protect the operator in a normal seated poistion (vs. leaning forward or either side) from falling objects (aka FOPS - Falling Object Protection System) in including their hands both on the steering wheel or hydraulic control valve levers in any position. Further, the Drivers OHG shall not have openings between top horizontal members no greater than 6" betwen members. Bottlers are famous for requested expanded metal tops to be instaledd onteh DOHG. Most every one I have know - manufacturers & or distributors will not condone the removal of the OHG for any reason. This why you'll see most lift truck designs in the last 10-15 years, maybe longer, with the OHG welded as intergal part of the frame or a side member. I once was a a very large glass plant in Ohio in the mid 70's & in their gullet room (a low overhead @ 8' high area, place below ground where melted old glass is collected as it dropped down from an above furnance via a forklift with a fork mounted bucket). The cullet was scopped up, lift and dumped in a hopper. Well, this lift had no LBR or overhead. But in various places there were metal I-Beam type structure extending straight down from the sealing - can you day a decapitation wainting to happen. Thsi truck was part of a 40 truck fleet that we were bidding on & they wanted to replace it with a new one on a FMV lease w/ Fill Maintence program. Our legal council advised us to bid on 39 units because of PL concerns. I understand OSHA shut this operation down & the company revised this operation to be compliant.
Thse exact standards may have been updated since 2007 as that is when I retired after 41 years of lift truck stuff.