I've upgraded to 5.2.3 from version 4.9 and now all my previously installed modules (most notably ActiveSocial and ActiveForums) are gone from the drop down. The modules themselves are in use and function but it seems like I have to re-install them to get them to appear in my drop down. Is this correct?

The modules are NOT listed here. That is part of the problem. I have installed them. They are still in use on pages, but they do not appear in Host>Extension or Admin>Extensions. I cannot add new instances or even delete them

O.M.G. That is not an option to take lightly. This site has over 120,000 users and upwards of 200GB of content (data and files). The thought of losing another day for restoring the backup and then re-applying the upgrade is too much for me to consider at the moment. Especially considering the cost and time to buy and apply DNN5 versions of the modules. Plus I will lose a full day of activities after this upgrade. Isn't there something I can do in the database to make them appear? the data is obviously there I just need to let DNN5 know about it somehow.