First of all, precious little of the modern Rider Back line is rare these days. They were manufactured in the millions of units.
Second, I moved your topic to the Plethora and merged it with a pre-existing topic on the subject. We reserve A Cellar of Fine Vintages for topics on decks that are at least 20 years old.
Today, USPC still makes and sells the Classic box style, and they call it Bicycle 807. It's likely because of that barcode and serial number from the older 807-R-TG. The cards inside are identical in all ways to the cards found in any modern "Standard" style Bicycle Rider Back box, right down to being made in Kentucky. It was a "gimme" to collectors who preferred the older box style and magicians who have crafted tricks/gimmicks dependent on the older box style (there are many). While not commonly available, as you've noted you can order them online easily enough (
Wingra Direct/shopbicyclecards.com carries them - they're owned by USPC and carry all the current mass-produced stock) and many magic shops and card dealers probably have them around or can order them. They're probably as hard to find as a late-model pack of Tally Ho.
The 807-R-TG is only rare in the sense that it's no longer in print (well, the box is no longer in print - the cards are another story). It's unknown exactly how many were made, but as far as I know, it came into use just prior to the shift to Erlanger and the release of the newer "Standard" box design. It appears to have been mass-produced, making it not too difficult to find - but it's a matter of talking to a retailer who knows what you're looking for, and most won't. The sticker seal is almost certain to be black and the cards inside are likely made in Erlanger, despite what the box says. If the seal is blue or red, it might be Cincinnati stock, but I haven't seen any of that model with a seal other than black. Black-sealed decks from the late 2000s are almost to a deck made in Erlanger. They used up the leftover boxes from Cincinnati, filling them with Erlanger-made cards.
The newer 807 boxes have the same exact barcode as the older 807-R-TG boxes. It's probably why they came together in your shipment - USPC and retailers consider them as essentially the same product; the new or old packaging to them makes no difference.
