No4 vs SMLE No1MK3* extractor spring

Are The No4 and the SMLE No1MK3* extractor springs interchangeable?

Just had this question asked to me.....embarrassed to say I don't really know the answer!

I have never changed an extractor spring on a No1......and don't have one in front of me to compare.

Thanks.

I think that all No4 (& No5) extractor springs are the same, but they are distinctly different to the much more solid looking spring for the No1 rifle.