I had a pair straight from Altec, so they do exist...some G are also Tangerine...
I have mentioned before, parts change dates were not hard and fast...I suspect initial runs of, say molded parts, were small...I mean you don't wanna have a million misshaped ones in stock...so do a few hundred to test. Then, if you happen to run out of old parts, and have new ones sitting....well, it's just economics.
I have seen newer date codes with old parts, and vice-versa. ESPECIALLY if used in cabinets, rather than retail.
Or could be H production is ramping up, and people are still ordering G's...so you slap G stickers on H's? Dunno. I was back in retail by then....