Newbie Daytona Owner - Advice/Help please!

[M3 Rolex]

Hi guys n girls!

As Per my first thread, i am the proud owner of a Stainless Black Dial Daytona

I bought the watch at the end of August this year, now my question to the panel of experts (!) on this great forum is this......

My watch is an M serial with the 78490 bracelet.

From reading on here, it seems that this is an slightly older version, and could have been sitting around at the AD for almost a year before i bought it, which i know would not affect warranty as the warranty starts from the purchase date, but would a watch 'just sitting around' for almost a year be a 'lesser' purchase than a totally factory fresh or more recently manufactured one?

Would this 'idle' period affect the longevity of the watch!?

the AD assured me that its 'fresh' stock, but from research on here and on the rolex reference guide it seems as it isnt!!

whats the score guys?

Thanks in advance!