I think the OP meant separate antenna because Keystone used a cheap omni directional antenna for TV/FM/AM.
That works great if your camped between the transmitters of the AM and FM stations, as in a parking lot next door to them, and within 10 miles of the TV station, with a clear line of sight to it. The dealer is probably making the case that since this is what Keystone provided, that's what you get. Good luck dealing with Keystone even if you have a decent dealer involved.
I also believe the OP has a Springdale. I've never heard of a Keystone Silverdale. I think a Silverdale is a ham?