Moira (60) and Colin McNicol (61) said the venue was recommended by a friend and they had memories of Jim’s fatal crash on April 7, 1968.
Colin was in Germany and his family were told by people who had seen the news, while Moira remembered coming home that day and her sister was in tears at the news.
To mark their part of the new museum’s history, they were presented with a host of Jim Clark goodies, including a print of him competing in the 1965 Belgian Grand Prix. They also met Doug Niven, Jim Clark’s cousin.
The museum, operated by charity Live Borders, celebrates the life and inspiring racing career of Jim Clark – one of the Borders’ and Scotland’s leading sporting figures – with an interactive experience.
As Scotland’s first, and double, Formula One World Champion, as well as Indy 500 winner, he is one of the greatest racing drivers of all time.
Shona Sinclair, curator for the museum, said: “I am so proud of the team and proud to have worked on this project.
“It’s an amazing accomplishment for us to welcome our 10,000th visitors three months after opening.
“Huge thanks to Moira and Colin for being an important part of our history.
“We look forward to celebrating more milestones as we look ahead to the new season.”
The facility was designed by Scottish Borders Council architects, who worked in partnership with charity Live Borders and the Jim Clark Trust on the development of the project.
Formula One legend, Sir Jackie Stewart OBE, officially opened the museum at the end of August.
It includes two of Jim Clark’s race cars, image galleries, film footage, interactive displays and a simulator.
There is also expanded exhibition space showcasing memorabilia and the trophy collection.
Funding for the £1.6million partnership project has come from Scottish Borders Council, the National Lottery Heritage Fund, Museums Galleries Scotland and the Jim Clark Trust – the latter including a grant from the Fallago Environment Fund and individual donations from around the world.
Adult admission to the Jim Clark Motorsport Museum is just £5, with visitors able to return as often as they like for free for the following 12 months.
There is a small additional cost for the simulator.
Jim Clark won the Formula One championship in 1963, becoming the then youngest ever World Champion.
He followed it up with victory again in 1965 and in the same year won the prestigious Indianapolis 500 in America.
He remains the only driver to have won both the Formula One and Indy 500 titles in the same year.
Clark tragically died iin an accident at the Hockenheim course in Germany at the age of just 32.
He was much admired for his modesty and humility alongside his remarkable natural ability in all forms of motor racing.
He is still considered one of the greatest ever racing drivers and remains, to this day, one of Scotland’s most admired sporting heroes.
The Jim Clark Motorsport Museum is open Monday to Saturday (closed Wednesday) from 10am to 4.30pm, and on Sundays between 1pm-4.30pm.