I was wondering the same thing as to whether this is a true Pentax-sponsored website. I did find these comments online, about different authorized and non-authorized Pentax stores in Singapore:
Who is the real Pentax Distributor in Singapore? | Shutter Journey (SGP)
Poking around online, I see that there are two different facebook pages for pentax distributors in Singapore. The seller referenced in the original post in this thread (pentaxwebstore.sg) has
www.facebook.com/pentaxsingapore; that facebook page also has comments on it that suggest it is associated with Emjay Enterprises, which the article on
Shutter Journey (SGP) | Advocators of Carefree Photography indicates was the Pentax distributor until 2013. But the current authorized distributor mentioned in the comments I found--Audio and Photo Distributor (FE) Pte Ltd--has a different facebook page,
https://www.facebook.com/AudioPhotoDistributorSingapore.
Pentaxwebstore.sg and Emjay Enterprises have the same mailing address.
Audio & Photo Distributor's page claims to be the sole distributor of Pentax & Ricoh in Singapore. Audio & Photo Distributor's webpage (
Audio & Photo Distributor (F.E) Pte Ltd) doesn't seem too up to date, but they appear to be the long time Ricoh distributor. So with Ricoh buying Pentax, maybe the distributor got changed at the same time.
Also see
APD Singapore | Shutter Journey (SGP) . If you scroll down the page to the summary description of APD, you'll see here as well that it claims to be the sole Pentax distributor.
So here's my guess: Emjay Enterprises (d.b.a. Pentaxwebstore.sg) was the distributor until the end of 2012. Then Pentax shifted distribution to the pre-existing Ricoh distributor in Singapore (APD). So is Emjay/pentaxwebstore selling off remaining inventory cheap (which would be why most of the lenses are not currently in stock)?