2 different surface finishes on a single PCB?

[smoothVTer]

Does anybody have experience with the using 2 different surface finish on a single PCB?   

For example, my application includes non-soldermasked areas intended for snap-dome buttons.  For longevity, the recommended finish for snap dome buttons is hard gold.    These exposed metal button areas are smaller than 1cm in diameter.   The remainder of the PCB can use HASL.   I am wondering about the possibility of doing a 2-step surface finish process and whether doing 2 finishes would make the cost of the PCB higher than just doing a single-step full gold finish all-around.   

Of course I realize I could ask the manufacturer directly, but want to ask here first to avoid any 'gotchas' or pitfalls before making my inquiries to the fab.   By the way, these PCBs will be made in China. 

[Gribo]

It is possible to use hard gold for certain parts (Dome pads, edge contacts) and HASL for other parts, I had one design with such setup, However, the fab charged extra for this, as it is another manufacturing step.