Liberia Scott # 333-37 & C68-69, Issued in 1952.  MNH COMPLETE Set INVERTED CENTER CORNER MARGIN BLOCKS.  There is no # 332 as it is a single color stamp.  Seldom seen as a complete set, especially for blocks and corner margin blocks at that!!   Scott lists only 334, C68-69 inverted, CV $50 each stamp.  von Saleski lists 334, 335, C68, C69 only.  The other values, 333, 336, 337 are unlisted and are scarcer than the listed.  CV is conservatively $1,400 for four sets of singles valuing the unlisted the same as the listed, which is an undervaluation.  Blocks command a premium as well. 

All blocks are corner blocks but they may differ from scan, some may be oriented to different corners of sheet and some may have margin or plate number inscriptions.

Shipping to the US is via insured mail for $5.00 and via registered mail for $24.00 to all other countries.