When creating small PCBs, it is often convenient to panelize them for higher volume production. In my package of gerber files, I include all the layers for one image, and then include a PDF detailing the dimensions of the panel.
This has worked great for ordering PCBs from multiple fabricators, but when we presented the PCBs and gerbers to the assembly house, we were asked to provide fully panelized paste layers so they can order the solder paste stencils.
I worked at an electronic assembly house for 8 years, and we always panelized the paste layer for the customer. Is there an industry standard expectation for this?