Not a bad experience, just strange....I was originally scheduled on DL 673, LAS-SLC but I used the change itinerary option on Delta.com to switch to an earlier flight DL 1452. Equipment was listed as a 737-800, all coach configuration. Seat map showed best seat available was exit row window 13F, and after checking seatguru.com, this is what I selected and was assigned. About an hour later, I rechecked Delta.com to see if an aisle seat had opened up. To my suprise, row 13 was no longer the exit row. Row 17-18 were now exit rows and all exit row seats were open. I selected and was assigned 18D. The seat map on Delta.com and Benedelman showed row 1-4 and then 10-32 all in coach configuration. Rows 1-4 had seats A, B, C on one side and then just D on the other. Seats E and F on rows 1-4 did not exist on the map. Thinking this was strange, I tried to request upgrade but it showed no first class cabin on this aircraft. No big deal, I was happy with my exit row aisle. So, I get to the airport and check in at the kiosk only to find that I have been reassigned to 4B, which still is showing as a coach middle seat. Not wanting a middle seat, I switched to 18F as 18D was gone. At the gate, I asked agent why I was reassigned to a middle seat and she informed me that the aircraft did indeed have a first class cabin even though it did not show this online or at kiosk. She said that she was the only person able to upgrade anyone on this flight and she had upgraded all mediallions and that I had unknowingly downgraded myself at the kiosk. She admitted that map did show 4B as a middle seat but assured me that it was indeed a FC aisle. Luckily, 4B was still available and she gladly re-upgraded me. She laughed and said that she was suprised that I opted to downgrade myself. I explained why I did it and she said that I should trust that they would do the right thing for their best customers.
On board, comfortable in 4B, yes a FC seat, I was surprised that 4 other FC seats were taken by deadheading FA even though flight was totally full. Another stange thing is that inflight drink was served by FA with a cart. He served FC and then continued to move to coach as if it was a full coach config. I was given a bag of peanuts with my drink and I asked if he had any of the other snack selections available. He said he could get it if I wanted, which I did. He brought me the cheese and crackers but did not offer to any one else in FC.
All in all, things worked out great. I got FC on a flight that should not have had it, gate agent was very friendly and I arrived home safely and on time.