Just seen a post on a volvo forum for these, they are old style looking inertia safety belts, brand new and quite expensive, but they look great!
!http://www.vwheritage.com/vw_spares_Seat-belt-front-chrome-inertia-tan-BS-std-use-12-71-ONLY_act_shop.product_pID_142178_lang_EN_country_GB.htm?crumbPageToLoad=1