You can add it there but it might also be more effective to add right above any location where you have any contact information as that might apply to why they are contacting. Again no guarantees.
I do use 3D printing with my own projects now, so I follow and contribute to several 3D printing FB pages.
The very first question usually posted after anyone puts up a picture of their own printed models is: “Where did you get the STL file?” The next question is usually, “Can you send me that file?”
The demand for free/copied files is so prevalent that it’s become almost a cliché or a joke.
“Fine” scale modelers are actually way behind other modeling genres in this regard. Tabletop gamers and (mostly) fantasy figure modelers have been engaged in 3D printing a lot longer since larger scale “figgies” can be printed using FDM (“string printers”) which were the first consumer types available. (Also, younger modelers who engage in those genres are also more tech-computer savvy and tend to dabble and “play” with tech, so 3D FDM printers are very familiar to them.)
It won’t be long before “fine” scale modelers asking for free STL files also become a bit of a cliché.
(Full disclosure: I do most of my own 3D design and printing for my own modeling projects. I do occasionally share files with other 3D printer-designers who I know and collaborate with on projects. However, I never give any files or designs away outside of this small circle. I have on even rarer occasions, printed parts of my own designs for other modelers, like guys in my model club or other modeling friends.
I have also transferred ownership of some designs that I printed as “masters” for resin cast copies to, again, a few friends who are small resin AM vendors. I considered this both a form of collaboration and sort of quid pro quo deal - I get the parts I want/need and they get a new product to add to their offerings. In the past, I’ve also done the same sort of deal with resin AM vendors with hand-mastered kits, conversion kits and parts.
Finally, I have presented a two-hour “Introduction to 3D Printing for Modelers” seminar at the IPMS Nationals, 2019 Chattanooga, TN and at a couple of other shows. The main content of this seminar was serialized and published in the AMPS Boresight magazine.)