Question regarding proper gas line shutoffs

[chris vis]

A 1971 multi family aparment unit had numerous gas shutoffs installed of this type. I could not find any "WOG" markings on the fittings. is there any other way to distinguish that these (blue handle) shutoffs are not water line shutoffs? If so, how would one tell with certainty?

[Markus Keller]

I could be wrong here but I've never known gate valves to be approved for gas. (the blue handle one)
The other issue is the old boiler gas valve. (the silver one in Pic 2)
A- those are known leakers
B- that one looks like it might have a plugged pilot tube tap, if so definitely get that thing out of there.
Recommend client get rid of both and install one new approved gas cock.

[Steven Saville]

The valve with the blue handle is a compression stop valve (it's not a gate valve) and definitely not allowed for gas service. The packing is prone to leaking around the packing nut and the internal washer is likely not compatible with natural gas.
As mentioned, both valves should be replaced with a proper gas cock.