It could be the original Black Leatherette Vinyl with Black Courorouy inserts.
The only way to know if it's original to your own 1970 914/4 is to either have the original sales documents noting it, or a Certificate of Authenticity (COA), or to get Porsche's new versions of the COA from the Porsche Classic in Germany (for you in Sweden & others in the EU/UK) - check via your Swedish Porsche website.
Porsche Classic website may also have photos of the paint & upholstery folders that were given out by dealers.
Also, Jeff Bowlsby has them on his 914 website:
https://bowlsby.net/914/Classic/PaintFabrics.htm From above link - Shows Black Courorouy was a choice:
.
https://bowlsby.net/914/Classic/ As well as some good info at p914.com (& .net & .org).
Jeff's 914 Assessment Form may also be helpful to you in figuring out your resto plans.
http://bowlsby.net/914/Classic/zTN_Gen_914CAF.pdf .
PS - Once you know what fabric was original to your `70 914/4, then you can try Lakewell.com &/or a local upholstery shop - preferably one that specializes in 1960s-70s Euro cars.
https://www.lakewell.com/en/porsche/914 .
Good Luck &
Cheers!
Tom
///////