Playboy filed to renew the rights to a retro version of its Playboy bunny mark on a ton of its packaging and other items that'd typically feature the regular logo.

According to docs, obtained by TMZ, they're looking to lock down the image of a smirking white bunny in a tux and plaster it on pretty important Playboy merch ... like magazines, for example ... plus calendars, boxes, stationery materials and LOTS of other stuff.

The move's interesting, especially considering Hef died just last month. Some might have seen it as a signal to potentially change the branding ... but Playboy says that's not the case.

A rep for Playboy tells TMZ .. this "new" bunny ain't all that new -- it's been used by the company before, having appeared on the cover of their February 1960 issue, and has popped up over the years. We're told Playboy is simply trying to re-assert its ownership of this version of the Playboy bunny, and that it ain't changing their iconic logo.