Wel yes but I'd say it is quite a task to do and what you'd end up with is would be only partly up-to-date.

Consider the bugs in the non-open parts that are very difficult to fix without access to the source, a good example is @thp's emojifix
This is a crazy stunt involving a drop-in library that has been hacked by patching the broken code manually in the binary! That's at least an order of magnitude more difficult than a simple source fix would have been