D3060280A.jcv is native to nuvi 7x5 devices using full screen views, it has a length of 868,205,210 bytes (~827MiB) and 123,525 views with picture size of 480*270 and is fully compatible with your 1390.

D3191270A.jcv is native for later released devices such as nuvi 2xxx/3xxx> using split screen views, it has length of 509,166,591 bytes (~485MiB) and 125,992 views with picture size of 212*234 but will display in your 1390 as I said in previous post. The fact it has slightly more views than the big full screen file yet is only a bit over half it's file size is explained by the smaller picture sizes of the images, 212*234 vs 480*270.

D3153280A.jvc is (I think) the 'cut-down' full screen version Garmin offers via GarminExpress for 1xxx series in NA. Length is 26,499,137 bytes (~25MiB). It's got only 19,682 views. If you want it let me know 'cos I've got a copy. It's pretty-much useless though with only around 15-16% of the views of the other two files.

I don't really understand your question about Drive variants maps and JCV files, what exactly do you mean by 'changed'?