LHL & CHL smkey both happen to be listed in TGT (unknown).
Can't see it being a C or G as those usually have a clear(ish) line at the top coming back down.
On some stamps if the first letter came too close to the mold design they did modify it (as in this could be an L with the top leaned forward to avoid the smkey design). On many stamps we see the same letter twice but they don't look the same for this reason.
Someone put up a CCC chip on here lately and all three Cs were different.

But then again my eyes don't have as many years of chip seeing as all you experts...lol

I'm just glad to see even you guys don't always agree on these letters.
I can't figure out half of them.