And it was indeed prudent for gun owners to be quiet about their gun ownership back then, even to the 1950's, since gun owners were then considered radical - parents would advise children to cross the street walking home from school, if a known gun owner was on the route.

The (in)accuracy of gun ownership surveys
POSTED BY DAVID HARDY · 1 DECEMBER 2014 11:05 AM

It's been widely assumed that telephone surveys of gun owners understate the real numbers, because some proportion of them are reluctant to disclose ownership to a stranger. I recently found two pieces of research on the question.

Arthur L. Kellerman, et al., Validating Survey Responses to Questions About Gun Ownership Among Owners of Registered Handguns, 131 J. OF EPIDEMOLOGY 1084 (1990)... yes, that Kellermann. They surveyed 35 households in Seattle and Memphis (I wasn't aware that either had registration) who had a handgun registered to them. 31 said that they did have a gun, 1 denied ever having had one, and 3 said they'd had one, but didn't now (which the study counts as a valid answer, but I'd classify it as fishy, at least). So 3% gave an incorrect answer and 9% gave a fishy one.

Ann C. Rafferty, et al., Validity of a Household Gun Question in a Telephone Survey, 110 PUBLIC HEALTH REPORTS 282 (1995). A larger sample (around 190) of households that have a registered handgun, or had a hunting license. 13% of the first and 10% of the second denied owning any type of gun.

These suggest that telephone surveys result in numbers that are significantly too low, as by an eighth to a tenth, even when the ownership is completely legal.
http://armsandthelaw.com/archives/2014/12/the_inaccuracy_.php

11:30 pm ET
Mar 22, 2013 POLITICS
Guns Present Polling Conundrum

***snip***

Questions about gun ownership don’t fit neatly into typical polling categories, pollsters say. On the one hand, the question of whether the respondent owns a gun, or whether there is a gun in the respondent’s home, should be “really cut-and-dry,” Dimock said. But some guns may have been inherited and may hardly be used. “It’s there but not present in people’s mind or their lives,” he said.

Who answers the phone in the household could affect responses. “We know that in a survey where respondents are randomly selected from adults in the household, a household headed by a married couple is substantially more likely to report guns in the home if the husband is selected than if the wife is selected,” said Philip Cook, an economist and gun-violence researcher at Duke University.

Also, some gun owners may be reluctant to tell researchers they own guns, because of legal and political considerations, which makes the question more like behavioral or attitudinal questions than like questions that ask basic facts about respondents. “This is an unusual demographic-type question,” said Frank Newport, editor-in-chief of Gallup.

That is the argument cited by those who think Gallup’s higher counts for gun ownership are more realistic than lower counts from the General Social Survey, which is run out of NORC, an affiliate research institution at the University of Chicago. Gallup’s survey, and some others that count more gun owners, are conducted over the phone, while the GSS is fielded in person.

“People are very reluctant to admit they own guns in phone surveys,” said Andrew Arulanandam, spokesman for the National Rifle Association, which uses Gallup’s numbers, not GSS’s. “We suspect they would probably be more reluctant to disclose that to someone at their front door asking them pretty personal questions.”(...emphasis added)
http://blogs.wsj.com/numbers/guns-present-polling-conundrum-1223/