Inland is not a ‘reseller,’ per se, as that would imply that they are authorized by the manufacturer to sell the product under the manufacturer’s own brand name.
Virtually every store brand of anything (potato chips, bed pillows and even 3d filament) is made for that store by a brand manufacturer. Sometimes it is changed significantly for the specific store that buys it and other times it is simply put into a different package with the store’s name on it.
All Inland brand filament is made by someone else - Micro Center does not make their own. Micro Center employees in the past have confirmed that all of their filament is made by either Polymaker or eSun, and used to tell you that the way to tell was whether the package had a logo with 2 green leaves on it. If it has the logo it’s made by eSun, if it doesn’t it’s made by Polymaker. On my last visit I noticed that many of the boxes now have a hexagon cutout while some are still oval. According to an employee at my local Micro Center, that is now part of the difference between manufacturers - the hexagon cutout is made by Polymaker and the oval cutout is made by eSun. He also said that it was his understanding that eSun was being phased out and all their filament at some soon future point would be made by Polymaker.
Now, that’s not to say it will work exactly the same as filament that is actually branded Polymaker - and I can tell you from personal experience that the PETG does NOT print the same. Likely, the formula is slightly different for Inland specs and Polymaker modifies it accordingly. That said, while Polymaker is clearly my preferred filament, I also use a fair bit of Inland and would consider it my second choice.