Jarrell,
If the solder flowed down into the length of the joiner, that's great; you don't have to see a shiny glob anywhere for it to be a good connection (It wouldn't flow if it was "dirty"). When in doubt about it actually flowing the length, just take your soldering iron tip with a little more solder and run it down the jointers top length. It will pull the solder and you should be able to see a little bit of shiny along the top. But, to answer your question...sure add a little more solder if you want to.
The only time you should have to unsolder regular track is for a change in your plans (adding a turnout somewhere, re-route, and etc.)
From my experience, there are only two ways to go about this:
1. Use a Dremel and cut at the joint, then clean the old joiner off (may require a spliced in piece if reconnecting same),
2. ...or heat the joint, pull track apart and then clean the joint. Trying to use a "solder-sucker" is not that efficient and is time consuming. Just heat, pull joiner off with pliers taking most solder, and clean up with file. Most solder should come off easily.
I wouldn't solder turnouts which are more likely to have a maintenance problem. My 2 cents.