It appears to be an authentic Rimowa Salsa.
But your caution is well taken, as the Rimowa company itself advises to be careful with fakes. Criminals selling forgeries are no longer just in the back alleys, or at flea markets, selling out of the boot of a tired vehicle. This is especially true around the Christmas holidays with all products when everyone is shopping for bargains on the internet, or not.
As mentioned above, ALL Rimowa cases have a stamped authentication number, which can be traced and verified. That alone is a very good feature. You can always ask the seller a question, as stated above. If a case were purchased on EBAY using PAYPAL, and later found to be a forgery, it would fall under the " item recieved not as described " buyer protection clause.
To effect that clause, a complaint is first opened with PAYPAL or EBAY, the item is documented ( item received broken, a fake, missing parts, does not work as it should, etc.) including photographs, and further documented as finally being returned to the seller. Reimbursement from PAYPAL or EBAY back to the buyer's account is then processed, which is very quick.
I have not seen fake Rimowa products as yet, but went through this process regarding what turned out to be fake stereo headsets. I bought a number of these for the family, and was later alerted to the fact that these were fakes by another EBAY member who emailed me while travelling. I then filed a claim 37 days later when I returned. I had to round up the items ( my kids still wanted to keep them ) and send them back, but PAYPAL reimbursed my entire EBAY costs.
An useful and applicable addage I learned in Iran years ago buying Persian carpets: " Buy in the light, and sell in the shade. "
Ask questions and " put some light " on the item to be purchased. If the seller is obscuring or glossing over the facts, and it appears " shady ", then just walk away.