C:\Program Files\Steam\steamapps\common\Team Fortress 2\tf\download\models\freak_fortress_2
(The drive it is in may be different (C) but it's usually default, if you have another operating system let me know)
Maybe worth removing the files within the freak_fortress_2 and then joining our FF2 server, forcing your local machine to re-download the models. If this doesn't work, I have another idea but I'd prefer to go to direct messages for that.
Hopefully I've not given you advice that could brick your TF2. If it does, re-downloading TF2 is the worst possible outcome to this.