Four EPs in picture sleeves were pressed on London in Uruguay, as well as many singles during the 60's.
Clave [the local pressing plant for London] changed the grey labels for blue in late 1967 - early 1968.
No real promo pressings were made. Grey labels promo copies have an 'Muestra Invendible' ink stamp, whereas blue labels promos wear a yellow promo sticker on ['Difusion Venta Prohibida'].

No picture sleeves were made at all during the seventies and eighties.
Discography from this period, strangely, is more obscure than the sixties'.