27CXXX is an Eprom, 28CXXX will be EEPROM. The 27 series are either One Time Programmable if they are in a plastic package, or have a ceramic package with a quartz glass window for exposure to UV light to erase them. You can erase them by leaving them in direct full sunlight outside for 2 days. Otherwise under a UV lamp for a half hour, or you get special 15 second erasure units that do it really fast, and can give you a massive sunburn from being exposed to it in operation.
OTP units are not erasable ( if you have a high power Xray unit and a hour it will be erased, but that will also damage it) and thus you cannot test it by programming a bit. Only thing you can do is program a bit from a 1 to a 0, not the other way around. Chinese software also can have bugs, showing the wrong device type, though it did detect the correct device and programming voltages from the ID that some can be made to present to the programmer.