IS THIS A GENUINE TIFFANY BANGLE OR NOT?

Okay, any Tiffany experts out there? I need help as I think that maybe, just maybe, I've been duped again, but I'm not sure.

I attended an estate auction about a month back. They had 4 pieces of "authentic" Tiffany jewelry there. Whoo-hoo I thought! My lucky day. If I didn't buy anything else, I was determined to win all four pieces of Tiffany. Well I won and congratulated myself. So did the other bidders around me.

During a lull in the auction ..well a lull for me as they were auctioning off die cast car collections, comics, and all the crystal in the world it seemed (doesn't anyone value real crystal anymore ... this stuff was going for peanuts ) ... sorry, I digress. So while that was going on, I took out my Tiffanys and began examining them. Something didn't seem quite right on two of the pieces.  The weight of a necklace seemed too light for silver and a charm wasn't stamped. Hmmm... Then there was one of those bangles that looks like mesh: lo and behold, the Tiffany stamp was crooked. Okay. These had to be knock-offs. The other two pieces were harder to decide. Everything looked good with them. I got my money back on the two suspect pieces and told the auctioneer I'd be testing the others and to expect a call from me if I wasn't satisfied they were the real thing. Thinking back on it, why didn't I just hand the whole lot back!

Well we tested the silver when we got home and couldn't find any reason to believe the last two pieces were bona fide Tiffanys. We took photos so we could list them in OUR NEW SHOP at RUBY PLAZA (these weren't vintage enough for Ruby Lane) and were all set to go when my daughter stopped me dead: she questioned the 1837 logo on the Tiffany bangle shown above.  She'd been poking around the net and found a different logo for "1837 Tiffany" It wasn't fully oval with rounded edges. It actually had a hard edge with a little corner at either end. So, was my Tiffany bangle authentic or not? Wasn't it possible for Tiffany to have more than one logo over the years? After all, designers do modify their logos from time to time, don't they?

Well I spent several hours yesterday trying to find photos of authentic "1837 Tiffany" logos. It was hard to find. Nor could I find any written material on the logos. There was tons of really good information on eBay about how to spot fake Tiffanys. I learned a lot from that but my question is still unanswered.

You see, what I read on eBay is that real Tiffany is stamped thus in many cases:
Year, Tiffany & Co., 925 along with the copyright symbol. Well that's exactly what is on my bangle:

The spacing is perfectly even between the letters. The stamps are definitely engraved, not lasered (apparently if it's lasered on you can see dots under magnification ... not the case here). It's scuffed enough to have been worn and loved. The outer stamping (top photo) is consistent with authentic Tiffany. 

And now here's what's really confusing me:  I visited the Tiffany website in Canada and at the top of the page on BRACELETS is a photo showing that "1837" logo identical to the one on my bangle!! Click that BRACELETS link and see it for yourself... curved edges on that oval, just like mine! Below is a photo I found on eBay of the other logo:

Here's another : 

See how the "1837" logo is slightly squared on the edges of that oval? Not nice and round like mine ... or like the one shown on the Tiffany website!!

So I need help. What do  you think? Any Tiffany experts out there who can resolve this for me? I'd already listed this bangle in my RUBY PLAZA SHOP but I've taken it off for now until I get some definitive answer ... if I can. Can you help? Is this bangle of mine an authentic Tiffany or not?