The lens is glass. Lomo was a Russian company, I understand they have been taken over - or the name - and now make trendy-gauche, quasi-toy cameras with plastic lenses under the Lomography label. But the Lubitel is a real camera. It has no light meter, all manual, so you need to know how to use a hand-held meter and be able to set the diaphragm. This camera is stripped-down-basic and not easy to use compared to digital point'n'squirt, the Lomo would make a great trainer since it teaches you (economy and) the basics of photography as you use it: top shoppers, please don't knock this camera, we want to enthuse the next generation for analogue photography, not disillusion them with super prices for super analogue gear which will be well beyond what your average youthful photographer can afford.
There was some great gear which came out of the Soviet Union - if you can find a good'un - Kiev cameras have superb optics and the Krasnogorsk-3 clockwork cine camera is a favourite with film students. It has a great, bright zoom lens, weighs a ton, and is a joy to use if you survive the film loading experience Lomo also made cine developing tanks which are eagerly sought after and can handle both 8mm and 16mm film.