He always uses the MSOX3000 in his videos, so this will replace it, don't even need to include that in the contract.
In the industry this is known as "long tail" promotion. Companies send products to Youtubers in the hope they use it in future videos, and hence free promotion over a long time period.
One classic example of log tail promotion, and a company that doesn't understand it, is the Targano microscope in my videos. I've been using it for like a a decade now, not even calling it a "microscope" but instead I'll say (because I prefer saying it) "let's have a look under the Tagarno". Killer brand advertising in a ton of videos for the manufacturing cost of a single microscope. I recently asked them if they wanted to upgrade it to the 4K version to match my 4k teardowns and they said they weren't interested. Oh well, guess I'll have the find something else.
BTW, nothing against Great Scott of course, if you have to take ad spots to stay in business, definitely do it. And if reviews don't interest you then don't bother of course.