First, to address the initial question - yes, coxswains are recruited.
The volume of coxswains recruited is much smaller than that of rowing athletes - however, we estimate 100 or more coxswains are supported through the admissions process each year nationally. That is to say though that the process is extremely competitive.
Coxswains tend to be very smart. As such, many gravitate towards academically intense and selective institutions - which only increases the level of competition at certain programs - which may or may not choose to recruit a coxswain as part of their class in a given year.
However, it does happen and a handful of coxswains even see some form of scholarship. However, this is not the norm. Given their academics, we tend to coxswains elect to partake in the recruiting process because 1) they're interested in competing in the sport in college, 2) it offers a greater security in the admissions process, and 3) it offers an automatic niche for them once they arrive.
Coxswains are evaluated during the recruiting process in a number of ways. It is helpful if your coach has some familiarity with the recruiters at the schools you're interested in given the power of recommendation - however it is not necessary, nor is that the leading factor for most recruiters in the coxswain evaluation process.
Most college coaches evaluate coxswains on a different standard than rowing athletes insofar as their maturity, independence, demeanor, and level of organization during the recruiting process. This means approaching coaches directly and demonstrating an understanding of their teams and schools. Third-party recruiting services are not helpful in this regard, particularly for selective institutions.
Audio or video is requested by staff typically after initial bonafides are established. We have fair amount of material on this blog in regards to good coxswain audio.
In evaluating coxswains, many coaches seek a different level of understanding about the sport than they require from rowing athletes. If a coach asks how a race went, the answer "good" is sub-par. A succint self-evaluation of positives and negatives insofar as the athletes' own performance goes much further and also shows the pre-requisite level of experience and thought necessary for progressing onto the collegiate level.
Experience itself is an important factor. We've put together advisory standards for coxswains and their families to understand the levels of skill progression in the coxswain recruiting market with the additional understanding that different schools recruit at different levels; specific schools' coxswain recruiting standards are listed in our college databasee, or coxswains can use our recruiting wizard to help them determine their current possibilities.