PCB SMA connector 3GHz and 18GHz

Hi,
Is there physical mark/sign that helps to recognize the 3GHz SMA from the 18GHz SMA connectors?

Pin diameter is smaller, the spacing of the ground attach lugs is 3x smaller, etc.

I'm partly confused, because my standard suppliers (Huber&Suhner, Radiall) only offer SMA for 18 GHz and 27 GHz extended frequency range. Nothing about 3 GHz.

---------- Post added at 12:40 ---------- Previous post was at 12:23 ----------

I see, that some cheap SMA products have a 3 GHz specification, but I don't detect any dimension differences.

The below linked datasheet of straight PCB jack has an explicite 18 GHz specification, but standard dimensions, as far as I'm aware of:

http://www.farnell.com/datasheets/302309.pdf

I found the datasheet for both types, but i didn't catch any difference.
The 3GHz SMA is here and the 18GHz is here.
I buy the SMAs without package usually, so i think this is a serious issue.. i think!

I expect, that the only actual difference is in the mechanical tolerance specification (which expresses as maximum VSWR at 18 GHz). So you possibly get same performance with the nominal "3 GHz" type.

mmmm.... 3GHz, 18GHz are numbers to express the maximum frequency of the signal which pass in the SMA metal without high losses/distortion...
therefore the SMA price of 18GHz is double the 3GHz as in the links that i gave.
maybe i'm wrong...

Involved materials of the electrical part are gold and PTFE in both cases. The connector body is die cast zinc alloy respectively (milled) brass, which makes a difference in achievable tolerances. In addition, not recognizable at first sight, the gold plating thickness and respectively number of plug/unplug cycles may be different. It can be as low as 50 for cheap products.

So if my circuit is working on 7GHz and I attach to it SMA of 3GHz, do you expect the circuit output will be effected noticeably by the SMA?

I think, I answered the question before. You may miss the guaranteed performance, most likely, you won't notice the difference.

OK.. thank you guys