Here is a cover sold by an American seller just yesterday:
The item is described as "Airmail Cover from Phnom Phen to USA 1992".
In my previous blog entries, I have repeatedly emphasized that in most cases dealers and sometimes catalogue editors do not know Cambodian philately more than you do, they often give inaccurate information and price evaluation. Here is another solid example of inaccurate information, the high sold price is a joke too, but it is not the focus of this blog entry.
The back of the cover is blank, only two Phnom Penh postmarks tied the four stamps franked on the front. The postmark date is nearly unreadable. Probably it is the writing in red ink "For 50th VOA Anniversary" and the supplementary VOA Washington DC office PO Box number in blue ink which makes the seller conclude it is a 1992 cover.
VOA is the Voice of America, an international public broadcaster of the United States. VOA was founded in 1942, so its 50th anniversary fell in 1992. Logic enough.
For serious collectors, it is important to be careful and observing. Other than the VOA information, the postage can give clues.
Cambodia experienced rapid inflation from 1986 to 1994. In early 1992, a 10g standard letter from Phnom Penh to the US cost at least 200r. Since the cover has only 43.3r postage, It is certain that 1992 cannot be the year of delivery.
According to my observation, the time which yielded mail of around 40r postage (to the US) was from the very end of 1987 to mid 1990. The 35r blue Apsara stamp was put into circulation in mid 1988, so very likely this mail would be from mid 1988 to mid 1990.
As a matter of fact, the 35r blue Apsara was mostly used on mail in late 1980s, in 1990 it gave way to the 50r purple Apsara.
It is unclear why the mail was later inscribed "For 50th VOA Anniversary", only the content of it can reveal the mystery.