There are at least dozens if not hundreds, of "double red" flowered camellia hybrids, no way possible to be really certain which cultivar you have. There is no DNA database for camellia hybrids. You can compare photos, and make a guess, but it will only be a guess.
Your best course is to label this "lost tag" Camellia hybrid, double red flowers, and go forward. This is similar to loosing the pedigree papers for a purebred dog. Sure, it looks like a purebred dog, but without the papers, it's not getting into the dog show as a purebred.
Good record keeping is part of good horticulture. Renewing or replacing brittle labels every 5 to 10 years, and keeping a written record somewhere as a backup is important.
I have a number of "no ID" orchids that can not be exhibited or used for creating hybrids because I lost the tags. So my comments are from painful experience.
Once the label is lost, provenance is lost, you now posses a "mutt". It is important to be careful with those sometimes annoying labels. If you don't keep the labels in the pot, store them with records that help you link label to the specific plant.
Buy extra labels, pencil on plastic labels faded slowly over a 10 years period. Magic marker and most inks on plastic are fugitive, fading rapidly in sunlight, becoming invisible in a very short window of time. For me magi markers last nice about 2 years, then in less than month will fade away completely. Pencil fades so slowly that you usually can with a little effort make out the writing even over a year after it was faded.