VIN#/Registration/Tag Issues for an Argosy- Help!

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My husband and I are newbies here, trying REALLY HARD to join the illustrious (and very friendly!) ranks of Vintage AS owners we've encountered here on the boards - thanks to all who've responded to different posts we've made over the last 3 weeks as our shopping as gotten serious!
The issue now as we consider putting in an offer on a '77 Argosy located in FL (we're in ATL and would travel to inspect and pickup) has to do with all the legal side of things, and trying to make sure we don't buy something that later gets taken from us b/c it was stolen many yrs before, etc.

The basic facts/questions I have (with asteriks) and what I understand after much research here and a visit to my local GA DMV tag office today:

-The VIN# according to the current owner, is: 28A7V1950

-VIN does not match the VIN sequences on charts, etc, I find on this site
***Is this an Argosy VIN, and where can I find info to decipher it? ***

-Title/registration reqs. vary by state, and GA does NOT title trailers
-This trailer has no known title (which I understand is common in many SE states on trailers before the mid-80's or so)

-This trailer IS currently tagged from Alabama
-The current owner in FL has owned it only a few weeks, and has done nothing to register/tag it in FL
-She has an undated BOS, and possibly, signed over Reg. papers from AL, from the person she purchased it from
-She purchased it from one of the AIRForums members, who lives in ARK, and makes his living buying AS from throughout the SE, and "flipping" them
- I have spoken directly to him; and everything seems "legit" on his side
- He thinks we can just use the BOS he gave her since she's done nothing with it
-(Obviously, we will make any offer contingent upon a satisfactory inspection on our part, either with or without a certified inspector, esp. as it seems odd that she is selling it so quickly after purchase)


- According to a GA DMV agent, to tag this trailer, I will need a 1)Bill of sale, 2)Registration info, if possible, and 3)a VIN inspection report completed IN GA by a GA police officer or County Tag Agent
-She gave me the form to be filled out for this inspection
-Obviously, this VIN inspection could thus ONLY happen AFTER we purchase the trailer and bring it home
-This Inspection would, thus, not help US in any way avoid buying "trouble"
- A GA acquaintance and frequent AIRForums poster who has looked at and purchased out-of-state AS had told me the DMV had helped them with VIN info before
- The DMV agent I spoke with in person today looked at me like I was crazy when I asked for this and stated, "We can't give you others' personal information, let alone the fact that we wouldn't have info in our GA database if it's not already tagged here"

BIGGEST QUESTION:

***What Can/Should we do to protect ourselves before purchasing the trailer, by way of getting VIN history, and would a site like "Carfax", or something else, even have records on old trailers?***

***Anything else you think we should know?***
Thanks SO MUCH for reading/responding to this LONG post,
Susan