The trunklids on the 1961 Dodge models have different part numbers than the 1962-63 Dodge Custom
1961 Seneca trunklid is part# 1919360 (for both 2-dr and 4-dr models)
The part# for the 1962-63 Dodge Custom and 1962 Chrysler models is 2253270
Not certain on why the new part# with the 1962 models but probably best to compare the two lids side by side to ensure interchange.