Hi,
Sorry for yours to be a little slack. I make my parts based on the rocker covers that i have at work and this is the first instance i have heard that the fitting was a little loose as others seemed to be ok.
I do not mind replacing them if you like, as i like to keep everyone happy.
On the other hand you can just put some locktight on them or even a dab of silicon to make them tight or if you get the covers painted that will work too. Its not nesessary to make them tight (individual choice i guess). The main thing is that they do not leak, and as its not under extreme pressures it is unlikely to leak.
Please let me know and i will try to help you out.
Hope this helps.
Karl