Plate blocks are typically worth more than just a block of four or mint single stamps. And condition/centering also matters, stamps with really great centering and in perfect condition are more sought after than those which are not. Additionally for plate blocks the condition of the perforations also matter; 'perf separations' or should those blocks which have been previously folded are worth less. Also note that some plate block numbers are less common than others; in fact some numbers are quite rare.
The plate blocks shown above are all relatively common and do not command much in the marketplace. For example, the last one recently sold on eBay
for less than 50 cents.https://www.ebay.com/itm/US-838-IOW...333197897599
If possible, post some images of the oldest plate blocks you have, these are likely to be the most valuable.