Thanks to Knob and Tube wiring this can be an easy fix, or a real PITA, depending on being able to identify the hot and neutral conductors, and if these wires were randomly switched in other locations in the circuit. You can replace the outlets with three prong, grounded units and protect them with a GFCI receptacle or breaker. Current codes require "tamper proof" outlets which are inexpensive and have a shutter that keeps kids and idiots from sticking things into the holes, and getting electrocuted. You need to label the outlet covers with both "no equipment ground" and "GFCI protected" labels. Most GFCI outlets and breakers come with both sets of labels in the box.
As for electrical knowledge in general, the best source is Mike Holt. This guy is a giant in the electrical field, and considered the guru of current code and best practice knowledge. Either add his name to a Google search, or look for his forum in the results. It's not too unusual to see home owner's forums, or even home and electrical inspectors forums, and You tube, offering either outdated, or incorrect information on electrical questions. You can take Mike's info. as gospel. Good luck.
This is what the code says , regarding your question.
Sec. 210-7(d)(3) permits any of the following installations when replacing a 2-wire ungrounded receptacle:
(a) Replace it with another 2-wire receptacle;
(b) Replace it with a GFCI-type receptacle and mark the receptacle with the words “No Equipment Ground;” or
(c) Replace it with a grounding-type receptacle protected by a GFCI device (circuit breaker or receptacle). Since the grounding terminals for the receptacles are not grounded, you must mark the receptacles with the words “GFCI Protected” and “No Equipment Ground”
