I may have something of an answer for you. But first, a couple of questions....
Do you have the box? If so, then what is the address of the Paris store on the back? That will give you an indication of the age.
I have been a fan of this house since late 2007 / early 2008, when I got into fragrance with LAP as my first niche house. Since then, I have collected a fair number of their bottles, and many samples.
I suspect that your darker bottle is an old bottle of intermediate age. It is probably older than my first sample, but not as old as my super-vintage bottle. I will post pictures momentarily.
The most recent LAP address, which I find on the boxes of recently purchased bottles is:
2, rue de l'Amiral de Colgny 75001 Paris
209, rue Saint HonorĂ© 75001 Paris
An address of intermediate age, which I find on samples and bottles obtained in 2008 and for some time after, is:
12, place VendĂ´me 75001 Paris
Finally, the oldest age I can find, which does not include a web address (late '90's, perhaps?) is:
26/27, PASSAGE D'ENFER 75014 Paris
I only find this latter address on my oldest bottles. None of my samples have this address. These apparently old bottles have octagonal (not heptagonal) shape and round caps. I have obtained four bottles like this - three with the oldest address, and one with the intermediate address.
Two of the ones with the oldest address are Timbuktu. They were colored as deeply as yours, or slightly deeper. I gave one to a friend and kept the other.
The smell of these old Timbuktu bottles is - like yours - unmistakably richer and deeper. Before they settle, they almost seem to have off-notes, which is very typical of old vintage. My first sample of Timbuktu, which predated 2008, smelled much clearer and more transparent when I first smelled it in 2008.
Now - here is some speculation / detective work.
Both of the Timbuktu bottles look remarkably like the ones that were at my old C.O. Bigelow, before it closed. The third old style / old address bottle is Mure et Musc Cologne, which I did, in fact, get at C.O. Bigelow when they had a 75% off sale. And the 4th one with the intermediate address looks like the same bottles of L'Eau de L'Artisan which were at C.O. Bigelow, and which I came close to buying.
Unfortunately, I missed the big sale on L'Artisan Parfumeur when C.O. Bigelow closed a bunch of its shops. HOWEVER, I'm pretty sure I still got in on the action, because I got my two bottles of Timbuktu and the one bottle of L'Eau de L'Artisan when Fragrancenet.com had a HUGE fire-sale on L'Artisan Parfumeur, shortly after that.
So - I think that your richer bottle is simply vintage Timbuktu. This fragrance definitely ages - but rather nicely.