Yes to question #1. But that does not mean the interest will disappear or be inadequate. One Verizon Iphone 4 I was tracking on Ebay yesterday had 50 or so people view the auction (based on the counter at the bottom) within the first 3 hours. Maybe 2 months ago it would have gotten 100 views in that time. What did it matter? Still sold through Buy It Now the same day. In terms of price, last month you could nab a 32GB Verizon easily for $340 to $360 (clean ESN, not damaged, etc.). I've seen a drop this week of about $30 or so. Not a scientific analysis but a general sense from my visits to Ebay.
P.S. Substitute "Iphone" for "car" in the questions you asked. "I recently bought a 2011 Lexus to re-sell and make a lot of money. Now that the 2012 model came out, should i expect to have less buyer interest? Also Should I expect it to be worth less money?"