Kinda, not really. It’s different per version of the client. The source on GitHub is usually super out of date and it’s unlikely the distributed version is built off the GitHub source unmodified.
The out of date source is mainly for the Android Telegram client, but not that much, it's usually 1-2 minor versions away at max.
https://github.com/DrKLO/Telegram
They just did delay pushing the latest version of source code, didn't they? I remember there is a help page which instructs you to compare the source of both GitHub and clients version.
tdesktop one https://github.com/telegramdesktop/tdesktop gets updated directly, not sure about the iOS and macOS ones.