Not sure why you were talking to the POI at a company you are trying to get hired at.

It's hard to judge the situation without reading the opspec in question but if it's as you described you may be in a bind in that you have to prove a negative...that all the captains you flew with did NOT have that qualification.

Normally someone with your kind of flight time would just carry that OPSPEC around in their hip pocket in case they get asked. What you probably also need is a letter from your employer stating that in accordance with their OPSPEC you were required as an SIC, and explaining exactly how that was derived from the OPSPEC.

Without that letter, you are at risk of getting rejected from any interview if you present SIC time in a single-pilot airplane. You might even get flagged for fraudulent flight time, in which case you will never be invited back even when you meet the mins.

Hope you get it sorted out.