Comment: I posted a summary of this cartoon in Gumby Does Hopi, but I hadn't seen the video until now. I've watched it and it's not too bad.
True, the Indian is a Tonto type. His English is clipped and he sports a headband with a feather. But other than these things, he's a decent character. He's not half-naked, wearing buckskins or a headdress, or waving a tomahawk. His skin is brown, not red.
Once Gumby, Pokey, and "Hopi" enter a book titled Hopi Indians--near books titled Wild Indians I Have known and All About Eskimoes--things pick up. The renditions of the Hopi corn field and pueblo are pretty accurate for a 1957 Claymation cartoon.
There's some stereotypical Indian chanting and music in the background. And the Indian's goat also speaks like Tonto. But these are minor issues.
The biggest issue is the cartoon's use of sacred Hopi kachinas (katsinas). The Hopi might say these figures are "taboo" and should never appear in children's entertainment. But within the Gumby framework, I'd say the cartoon portrays the kachinas respectfully. There's no egregious violation of Hopi beliefs like the infamous NFL SUPERPRO #6.
Give the cartoon credit for getting some basic things right. The Hopi do grow corn, live in pueblos, and pray to "rain spirits" called kachinas. That's more Hopi information than you'll get from 99% of Hollywood productions about Indians.
For more on the subject, see Native Videos and Cartoons.