For an IF filter, I'm planning on using a an off-the-DigiKey-shelf crystal
filter. I need (well, want) to match the filter to 50 ohms.

Could someone verify I'm interpreting the data sheets & terminology correctly?

Say I'm getting an ECS-10.7-7.5A filter, data sheet he
http://www.ecsxtal.com/pdf/mono.pdf ... I'm reading the "termination
impedance" as 1800 ohms in parallel with 5pF or, at 10.7MHz, 1800 || -j2975 =
1318 - j797.2 ohms. From reading the application notes on ECS's site, the
idea here is that -- for the filter to work as designed -- it wants to "see"
1318 - j797.2 ohms on both the input and output, correct?

I'm also thinking that just because the filter wants to see a certain
impedance doesn't necessarily imply that the filter's own internal impedance
is the complex conjugate.

Thanks,
---Joel