You need to identify assumptions as part of the assessment of capability gaps.

According to the BABOK® Guide, an assumption is a factor that is considered to be true for the purposes of planning and analysis, but has not been confirmed or proven. Assumptions are used to fill in the gaps of knowledge or uncertainty, and may affect the outcome of the project if they turn out to be false. An example of an assumption is the project manager’s belief that her project team members can program in COBOL, which may or may not be true, and may impact the project’s feasibility, scope, cost, and schedule1. References: 1: BABOK® Guide, version 3, section 10.25, page 336.