I set config.disableAllHeaderCode = 1 in my recent TYPO3 sites, as I want full control over the page template.
But this not only throws out the html tag etc., but also the default Js (which could be used to uncrypt mailto-Links.
One solution would be to copy this TYPO3-generated JS from the core code and insert it manually. Very simple: just set config.disableAllHeaderCode = 0, load the page once, copy the js, done. But, in case of an update or settings change, this might break.
So: is it possible to access this "default JS" via typoscript and assign it to the PAGE object?
Have a look at https://github.com/TYPO3/TYPO3.CMS/blob/master/typo3/sysext/frontend/Classes/Page/PageGenerator.php. You will see that the spam protection code is hardcoded and only added to the page output if config.disableAllHeaderCode is not set.
Therefore I don't see a possibility to do that. Therefore the answer seems to be no, unless you XCLASS the PageGenerator. I would just copy the JavaScript code; I'm using TYPO3 for some years now and wouldn't remember that the spam protection code ever changed.