This actually requires scripting.
Due to an issue @cgrunenberg would have to respond to, this also requires an external script. I have attached the script which should be put into ~/Library/Application Scripts/com.devon-technologies.think3/Smart Rules.
The smart rule should be adjusted like so…
Creation Date from Text_SR.scpt.zip (2.3 KB)
For @cgrunenberg:
This handler can’t be used in a smart rule embedded script…
on convertDate(scrapedDate)
return date scrapedDate
end convertDate
It does work in an external script, hence my approach above.