If you're in FL, then there's an OMFS externship that you can apply to at Univ. FL Health Science Center at Jacksonville. That particular OMFS externship allows and accepts first year dental students.
In my experience applying to OMFS externships, some are very stringent on their application requirements, many are not. Some require numbers, again, some do not. You're absolutely right, externships are externships, regardless, they'll take up one line on your CV.
Your toughest hurdle is to have your parent dental school cover you as a D1 on their liability insurance which the majority of the OMFS externships requires from their applicants/participants.
I, too, wanted to do an externship last summer as a D1, but I took the boards instead. As matter of fact, I was going to do one with UF HSC at jacksonville. Now that I have the board behind me, this summer will be my first official big externship.
Side note, I spend 3 days with OMFS department at Univ. MN last week during my spring break (I did this last year also), I had a blast. In a way, these are my two "unofficial" mini-externships. I saw, did and learn a crap load. I extracted teeth, sutured, gave injections, exposed to my first HIV/AIDS patient (my hand in his bloody mouth) in 12-hour shifts at a Level One trauma medical center in Minneapolis (HCMC). There is a definite advantage to have more dental education background behind you to go into an externship! For me, it was amazing to see and apply everything I've learned from Oral Surgery and Anesthesia courses/books into a clinical settings. Example, I learned what #73 forceps and what a seldon are from the book and when I saw it on the surgical tray, I knew what it was!
I learned how to suture in different techniques with what type of sutures and where from the preclinical labs with pigs foot, but suturing lateral border of the tongue and gingival tissue is a whole another feeling! But at least I knew how to suture and do square knots from books & courses!
Bottom line is this. I do encourage you to apply to an externship as a D1, but you will encounter A LOT of "unknowns". You'll see a lot of cool stuff, but it's so much cooler when you know what you're seeing and/or how to use it!
OMFS rocks!
Oh, how could I forget! I also scrubed up and assisted a OR procedure retrieve a bullet from a guy's head. The bullet enter the head from just anterior to the left tragus and it was stuck in the right buccal fat pad just underneath the right zygoma arch. The chief resident who was the main surgeon made the incision intraorally in the right height of the vestibule in the maxilla and there he did his thing!
