Typically SPIE is handled as a conference proceedings paper; if your research tradition does not know such kind of papers (for instance, for our domain of research this format is very rare) you should indicate that it is a full paper, a peer-reviewed full paper or an extended abstract. Just to make clear that it is not just an abstract or something similar.
From the ABSTRACTING AND INDEXING point of view, the problem in conference proceedings is the unequal treatment of these major services, but in general most databases treat conference proceedings as journals (ISSN).
Differently, one conference proceedings treated as a monograph. Then, of course, such a publication is treated like a book (ISBN).
Conference proceedings can be indexed in all services, if they have ISSN, because they usually treat them as journals (e.g. Scopus, DOAJ and Clarivate Analytics-WoS-CPCI).
In the case of CPCI each edition must be reported separately. In the case of Scopus, there must be at least two editions (from two years) because they are evaluating on the basis of content from the last two years. If the Conference Proceedings has an ISSN it is treated as a journal and once indexed, each subsequent edition is automatically indexing later.