Yes, I think you are correct. American English l in the onset of a syllable is velar, typically, while in the offset of a syllable it is uvular. The SPE feature system gives a good foundation for describing this with its three binary tongue body features high, back, and low, which apply to primary articulations or secondary articulations, and as well to vowels and consonants.
In the SPE system, velars and velarized sounds are [+high,+back] and uvulars and uvularized sounds are [-high,+back]. It is not clear to me about how [+/- low] fits into this scheme, so far as secondary consonant articulation is concerned.
The textbook consensus that syllable offset l in American English is velarized rather than uvularized has puzzled me, since it seems so obviously wrong. Maybe this is due to the influence of Peter Ladefoged, who, of course, did not speak American English.