The way I'd see it, it'll be more likely that he'd made less of a letter of recommendation and more of a general report about Sika village, and perhaps specifying Sika herself in said report. More so considering that he did go to her village for the purpose of studying her culture and learning more about her people as oppose to scouting out for potential students, which is something that IC the college actually isn't allowed to do anymore.
Generally speaking, people of the college giving others letters of recommendation before they even arrive to the college isn't a good idea for the simple fact that nothing guarantees the letter's safety. For example, when Sika was robbed, the thieve's would definitely tried to sell off the letter of recommendation as soon as they can. People making forgeries of recommendation letters, especially from college officials, is something the college itself would want to crack down on. Identify theft is very much a thing in this verse even with people who can read minds, for reasons which would also be explained IC. Perhaps not as much as say, investigating rogue mages who are practicing necromancy without licensing, but it's still important enough that they keep abreast of the issue. To that end granting someone a letter with official signatures and stamps to someone who isn't guarantee to be able to safeguard it is something the college would try not to do.
And yes, while there are exceptions, these usually only happen in equally exceptional circumstances, like if Melecus was dying and had no way to otherwise vouch for Sika, what with being dead and away from the college or any other mages who could recover his body. Not to mention an recommendation letter from a college member itself is often more scrutinized than one that comes from an outside source, such as a martial master or some such. As mentioned, the college does it's best to not be influenced by outside politics, both it's administration and it's regular members. That being said it also regulates itself as best as it can via these self-restraining codes of conduct precisely so other nations and people can trust the college to not use their considerable influence in both clout and magic to try and force their own goals to fruition, as the college wants to be a place of learning and research not a base of operation for an NGO superpower. If Melecus had some agenda to say, introduce more kobolds to the college simply because of his preference for them over other races, that would raise quite a huge issue because that shows favoritism, more so as he decided to grant this letter without anyone else's oversight.
Long story short, a letter of recommendation from someone who is actually from the college carries far more weight than one that comes from a reputable but unaffiliated organization, for example a different mage guild. For someone of the college to give one to Sika would have to imply either great carelessness on their part, or absolute certainty in the exceptional ability and even some level of personal responsibility for entrusting them with such an important letter. But, so long as you understand those implications, do what thou wilt,
@EliteCommander.
