Yep, you were right. Somehow I didn't realize I had the older 2.2.1 version. I installed 3.0 as you directed, and everything seems to have loaded fine. Thank you for your patience and help!
So I installed this just now, using OpenIV to install the "RDE Added Models" zip file in the Main File folder. Seven files are in the scripts folder which is in the main directory. I have ScriptHookV and ScriptHookVDotNet in the main directory as well. I have Visual C++ Redistributable for Visual Studio 2015 installed. Sooooo when I boot up the game via RagePlugin for LSPDFR, I literally see no changes whatsoever. Same normal cop cars, same cop models, same everything. NOT using a mods folder at all. This a fresh install of GTA V with only RagePlugin, LSPDFR, and RDE.
What's going on?