The Type 74 may be a straight copy of the LP-50. Jane’s Infantry Weapons has this to say about it: “The Type 74 portable flame-thrower is a direct copy of the RFAS LPO-50 flame-thrower so reference should be made to that entry for full details.”
I suspect that the latest version of the Type 74 has a different fuel mixture in its cylinders from that used in the LP-50 – but otherwise the two weapons are pretty much the same.
I raised the issue about Chinese flamethrowers because I suspected that the PLA had Type 74s during the Sino-Vietnamese War in 1979 – and so unit 328 in orbat14 would need to have an earlier start date.
Of course, the Chinese had other flamethrowers before the Type 74. They captured large amounts of U.S. WW2 equipment – including flamethrowers – from KMT forces during the Chinese Civil War. A few of these – and perhaps some Soviet weapons – may have been used in Korea. The PLA definitely had a specialised flamethrower unit by 1955 - as shown by this article in PLA Daily (the official journal of the PLA).
http://english.chinamil.com.cn/site2...ent_884576.htm
As far as I can tell there are no flamethrowers in orbat14 before 1981.