Not great on hk45 - TruGlo Brite-Site TFX PRO Sight Set for Heckler & Koch

I got the TFX for my glock 43 and love them. They are my new favotite sight. I was even more excited when I saw the improvements with the pro version- the orange circle, and the face of the fiberoptic being more enclosed in the metal. I Ordered the TXF Pro for my HK 45- Big difference. They don't sit flush with the slide, there is a 1-2 business card thickness gap below the sight (both front and back). I have them installed by HK so it wasn't an installer issue. I think the dimensions must be different on the slides between models. I now worry that the front sight will bend or break the fiber optic since it doesn't have the support from the slide.