Postal codes in Poland were introduced just in the 70's. Believing Wikipedia, it was 1st January 1973. But probably initially they weren't obligatory, as it was something new.
In the address:
62-560 Skulska Wieś
the house number is lacking. There would be problems with delivering it. I have no idea how the post office would behave, would they reject it or pass to the postman, who may just know this lady.
Writing the name of województwo (province, voivodeship) on the envelope is not obligatory. The recommended pattern in Poland is:
And 62-560 is a postal code of not only Skulska Wieś, but also all the area of the post office in Skulsk (which can be checked on the website of Poczta Polska - Polish national mail operator). So the correct addres would be:
Skulska Wieś [house number]
In such cases the village name is written instead of the street name.
If the letter is sent to a village with a post office and without street names (with house numbers only), there is no second line as in the address above and the house number is written after the name of the village/town/city with the post office corresponding to the post code. What if it's a village without post office and with street names? I don't know what is a correct version, but I would address it like the official example in the picture above writing the village name just before "ul. Cicha 132" (in the same line), separated by a comma.