Could the Scandinavian Defense accurately be considered a gambit


Yes. Black is offering a pawn for positional considerations. White does not have to accept for good or bad. But it is more of an exchange in the sense that black immediately recovers the pawn if white accepts.

if you asking about the nf6 lines. You can make the argument since technically, white can try hold on to the pawn via c4 ,its just well understood to be bad if white doesnt give it back soon.
IT at best immediately equalizes for white.

The 2. ... Qxd5 lines of the Scandinavian are basically a way of transposing into a Caro-Kann type formation, giving up a bit of time (with the Queen) in order to ensure that Black gets the position he wants (no Advance Variation, no Panov-Botvinnik, no Two Knights, no Tal variation, etc).
So:
The 2. ... Nf6 line is a gambit (which White should decline), and the 2. ... Qxd5 line is a Caro-Kann.