American Large Cent Identification Help Needed

I'd say 1838 on the first, the others are pretty well done for. Unfortunately, the die markers for Coronet and Braided Large Cent varieties are not usually date-specific, but specific WITHIN a date, which means that if the date is not known, there are few varieties that are unique enough to be attributable by themselves, with a few exceptions such as the different heads of 1839, the 15-star 1817, or the Knob Ear of 1855, or the slant vs. upright 5's of 1855-1856.

Since master hubs were used for multiple years, and the date was punched into the die, there are going to be numerous die pairs which are virtually identical save for the date stamped on the coin.

In the case of, say, a 1853 Braided Hair large cent, you are looking at the position of 4 reverse leaves vs. letters in the legend, the location of the tops of the 2nd 5 relative to the bottom hair curl, the distance of the 1 in the date from the point of the bust, the relationship of the left edge of the left base of the 1 to the closest denticle in a vertical line below it, and the location of the lowermost point of the lowest hair curl relative to the 8 in the date.

Unfortunately, excepting the leaves, all of those diagnostic die markers require the presence of a clearly visible date to identify. It's entirely possible that a description of leaf positions on the reverse for one date and die pair (say, 1853 Newcomb XX) might also apply to a completely different die pair used on a different date (say, 1852 Newcomb YY) -- since that die diagnostic is identical between both coins, you cannot conclusively determine whether or not the coin is an 1852 or 1853 simply based on the leaf positions without using the other three diagnostics, all of which require a visible date. Even with Coronet cents, where you are looking at the position of the star closest to the end of the LIBERTY headband (left or right relative to the headband), the leaves, the last berry on the reverse..etc. You still have multiple years that could theoretically have the same die markers. The mintages were simply not high enough, nor enough dies used, to create all that many situations where you can state with certainty "I know this coin is a Date X because these die markers occur ONLY on date x."

Prior to the late 1830s, the odds of being able to identify a given date based solely on die markers do increase, to the point in some cases that by the Liberty Cap, Chain and Wreath cents of 1793-early 1796 you can conclusively identify a dateless coin just based off the die markers!