Water intrusion in gen 3 bed

I’ve begun my reading and really appreciate the vast wealth of knowledge and experience on this forum.

I’m getting ready to put a Bedrug bed liner and Truxedo Truxport tonneau cover on. The liner is a longer-term install. The tonneau is to tide me over while saving up for the RSI Smartcap Evo Adventure. Even these 3 purchase decisions came with a lot of post reading.

I decided to tackle the water intrusion issue up at the front top corners by ordering the oem rubber plugs discussed on this thread link . I believe these are intended to be installed with the factory bed cover which I think has different rail caps?

I decided to use them anyway but haven’t found how they install. You’d think they’d be intuitive (and maybe they are with their intended application) but I’m not sure I got it right.

I test fit the driver side. It did require cutting out an inside corner of the stock rail cap to fit. Not too worried if it’s wrong, these caps are deeply scarred up so I’ve already ordered new ones.

Long story longer, I’m posting pics of how I situated the plug. If anyone can let me know if I’m headed in the right direction it’d be most appreciated.

Hope I dropped this in the right forum

Thanks!